GIDEON blog

Free Demo Latest Updates Video Tutorials
Subscribe , j x

Archive for the ‘Outbreaks’ Category

New Dengue Study Identifies New High-Risk Countries

Pathogen of the month: Dengue virus

 

A man using a sprinkler ULV type for kill mosquito carrier of Zika virus and dengue fever it outbreak in school at the rainy season.
Image: Sprinkling to kill Aedes aegypti, a vector of Dengue, during the rainy season.

 

written by Chandana Balasubramanian

Halfway through every Hollywood disaster movie, when all hell breaks loose, a few rogue scientists are brought in. This handful of experts would have predicted the disease outbreak or catastrophe years, or sometimes decades, before. But their advice would have fallen on deaf ears – until it was almost too late.

Meanwhile, in real life, a large and vocal group of researchers and public health organizations are sounding the alarm about Dengue as a pandemic-level threat in the near future.

The relatively good news is that Dengue, a vector-borne illness, is not transmissible between humans. So, we can prevent a full-blown Dengue pandemic if the global community of public health officials:

But why is Dengue such a colossal threat? Why is prevention important?

 

Dengue cases on the rise

Currently, Dengue cases are estimated to be anywhere from 5 – 100 million. This wide range is because many cases stay unreported, or the symptoms of Dengue are confused for other diseases. But the number of Dengue cases is expected to boom in the next few decades, with 60% growth by 2080 [1].

The latest study on the spread of Dengue is by Aliaga-Samanez et al. from Spain [2]. The study is the first high-resolution analysis of how the risk of Dengue transmission has been changing geographically since the late 20th century. The study uses robust databases like the World Health Organization (WHO) [1], and the Global Infectious Disease and Epidemiology Online Network (GIDEON) [3] to track and map global Dengue cases since the 1900s.

All Dengue experts agree that the number of Dengue cases is rising fast and spreading wide across the globe. WHO estimates that about half the world’s population is now at risk [4]. Aliaga-Samanez et al. identified that the Dengue virus (DENV) has been making a home in previously low-risk areas, potentially due to global warming and deforestation. The authors also report that while the Aedes mosquito is responsible for Dengue transmission, DENV can be spread by primates and could adapt to be transmissible by other vectors.

Tracking the geographical spread of the Dengue virus by different vectors is complex. According to the primary researcher Alisa Samanez, using the GIDEON database – “one of the most complete data sources worldwide on zoonoses” – to build their own database was a significant factor to track a zoonotic disease like Dengue.

 

Reported Dengue cases in different regions, 1980 – 2020

Graph illustrating Dengue cases in different regions, 1980 - 2020
Image: Graph illustrating Dengue cases in different regions, 1980 – 2020. Copyright © GIDEON Informatics, Inc.

 

Dengue mosquitoes spread their wings worldwide

While Dengue cases are primarily found in the tropical regions of Asia, Africa, and the Americas, this is rapidly changing. The study from Spain determined that other regions now at risk are South-East China, Papua New Guinea, North Australia, South USA, parts of Columbia, Venezuela, Madagascar, and even Japan and South and Central Europe. The study predicts that Dengue could spread to Argentina and South-West Asia, from Pakistan and the Arabian Peninsula.

Ideally, public health officials in these regions will begin training their healthcare professionals to diagnose and treat Dengue early and raise awareness among their populations.  

For example, initially, Egypt’s Ministry of Health dismissed reports of Dengue fever in certain regions. But eventually, they reviewed published reports of Dengue outbreaks in studies that used GIDEON’s clinical tools. This prompted them to develop a training program for their health workers for the early detection and treatment of Dengue [5].

Two significant factors accelerating the spread of Dengue worldwide are the 2.9 trillion U.S dollar global travel and tourism industry and climate change.

Many studies indicate that international travelers are at considerable risk for Dengue spread. Ratnam et al. from Australia concluded that Dengue infections in international travelers occur frequently and may be associated with substantial morbidity [6]. 

What is worrisome is that while Dengue is not directly contagious between humans, it is transmittable from an infected human to an infection-free Aedes mosquito. So, if a Dengue-infected individual travels to another country during the viremic or infection-spreading period, a native Aedes mosquito may bite the individual and become infected [7]. This newly infected mosquito can infect other individuals.

Additionally, climate change is a contributor because rising temperatures in previously colder environments are fertile grounds for mosquitoes to thrive. Higher temperatures also shorten the cycle of a mosquito picking up a Dengue infection and transmitting it.

 

Captured in La Paz, Honduras, this August 2019 photograph, depicted Dr. Liliana Sanchez-Gonzales on the left, an Epidemiologist with the Centers for Disease Control and Prevention’s (CDC) Dengue Branch, along with an unidentified Honduran physician, as they were examining the chest x-ray of a patient, who was on the verge of developing severe dengue. The x-ray revealed the presence of fluid in her lungs, possibly due to plasma leakage, as she was going into dengue-related shock.
Image: Captured in La Paz, Honduras, this August 2019 photograph, depicted Dr. Liliana Sanchez-Gonzales on the left, an Epidemiologist with the Centers for Disease Control and Prevention’s (CDC) Dengue Branch, along with an unidentified Honduran physician, as they were examining the chest x-ray of a patient, who was on the verge of developing severe dengue. The x-ray revealed the presence of fluid in her lungs, possibly due to plasma leakage, as she was going into dengue-related shock.

 

Why is Dengue dangerous?

According to WHO, severe Dengue is a leading cause of serious illness, hospitalization, and death among children and adults in some Asian and Latin American countries [4]. Severe Dengue involves severe bleeding, liver, heart, and other organ impairment, and plasma leakage.

Many Dengue infections are mild with flu-like symptoms, but a lack of awareness and early detection could lead to severe Dengue. And since the incubation period varies from four to ten days, it may be overlooked or misdiagnosed until it becomes severe. Additionally, because there are four different types of the Dengue virus, individuals once affected by Dengue can be re-infected up to four times.

The Dengue vaccine is only available in certain countries and, as per WHO, is restricted to those aged 9 to 45 and individuals previously infected by DENV. Hopefully, we get a better alternative. But until then, we need to raise awareness about early detection and treatment on the frontlines and track outbreaks closely.

 

Conclusion

If we have learned anything from the COVID-19 pandemic, it is this: the best disaster control is early detection and prevention. According to Aliaga-Samanez et al., Dengue is poised to be the next pandemic. Only through global collaboration, rigorous tracking, and preventive public health programs can we banish health catastrophes like a Dengue pandemic to the world of fiction – away from our collective reality.

 

Did you like this article? Please share it on social media!

Check out more of our latest content here

 

References

[1] World Health Organization, “Global strategy for Dengue prevention and control, 2012-2020,” World Health Organization, Genève, Switzerland, 2012.
[2] A. A.-S. e. al., “Worldwide dynamic biogeography of zoonotic and anthroponotic Dengue,” PLoS Negl. Trop. Dis., vol. 15, no. 6, p. e0009496, 2021.
[3] B. S, “Dengue: Global Status,” GIDEON Informatics, Inc., Los Angeles, California, USA, 2015.
[4] W. W. H. Organization, “Dengue and Severe Dengue Fact Sheet,” World Health Organization, 19 May 2021. [Online]. Available: https://www.who.int/news-room/fact-sheets/detail/Dengue-and-severe-Dengue. [Accessed 04 07 2021].
[5] Department of Tropical Medicine, Ain Shams University, Cairo, Egypt, “Dengue fever, Correspondence to Nadia A Abdelkader, MD,” Egypt J Intern Med, vol. 30, pp. 47-48, 2018.
[6] F. Irani Ratnam, “Dengue Fever and International Travel,” Journal of Travel Medicine, vol. 20, no. 6, p. 384–393, 2013.
[7] J. P. Messina, “The current and future global distribution and population at risk of Dengue,” Nature Microbiology, vol. 4, p. 1508–1515, 2019.

Disease Outbreaks and Economics: an Interview with Prof. Rodolphe Desbordes

“Our results indicate that factors fostering a disease outbreak in one country can quickly lead to the emergence of a disease outbreak in another country.”

Epidemic infectious disease outbreak with person analyzing virus strain and worldwide situation. SARS-CoV-2 pathogen causing coronavirus covid-19 pandemic disrupting social and economic life

 

In March 2021, the Journal of Mathematical Economics published a research paper, Spatial dynamics of major infectious diseases outbreaks: A global empirical assessment. The article explored the spatial dependence of outbreaks and the role of globalization, analyzing 20 years’ worth of major outbreaks in developed and developing countries. The study found empirical evidence that ‘local outbreaks of many different infectious diseases can quickly spread to other countries’. Mortality consequences were found to be ‘much more severe in developing countries’.

 

Economics professor Rodolphe Desbordes
Prof. Rodolphe Desbordes

We spoke with the author Rodolphe Desbordes, a Professor of Economics at SKEMA Business School, about the importance of this research and the reasons behind choosing GIDEON as the data source.

Prof. Desbordes has widely published in the fields of International Economics and Economic Development. His current research interests encompass applied econometrics, determinants of political regime changes, and the links between biodiversity, economic activity, and zoonotic diseases.

 

 

How did you find out about GIDEON? 

I was looking for data with worldwide coverage on outbreaks of infectious diseases. I was really surprised not to find this information easily (e.g. provided by the WHO). In a few papers, I noticed their use of GIDEON.

 

What were the reasons behind choosing the GIDEON database for your analysis? 

I am really an applied macroeconomist, often interested in very global issues. For this reason, I need databases with long (time) and wide (spatial) coverage to run estimations. GIDEON was the perfect database for the epidemiological project I had in mind. In addition, for a non-specialist, the information provided on each disease was crucial to a better understanding of disease-specific characteristics.

 

How could healthcare systems benefit from a more econometric approach? 

Adopting an econometric approach is useful to reveal broad patterns, isolate the effects of specific factors, and carry out projections. This type of approach must be done in conjunction with expert knowledge of local conditions.

 

What is the importance of taking epidemiological data into account in the context of international policymaking? 

Deming said that “without data, you are just another person with an opinion”. Data are essential to guide domestic and international policymaking. Lots of data still need to be produced, in order to strengthen surveillance systems.

 

Do you consider developed countries’ decision to donate COVID-19 vaccines a step towards achieving a GPG (Global Public Good), and do you see this becoming more commonplace?

Some people have argued that the current pandemic is a rehearsal for the coming climate change crisis. It is essential that developed countries stop acting as if they live on a different planet where bad things do not happen to them. An unfortunate advantage of global crises is that even self-interested rich countries contribute to the Global Public Good. However more needs to be done. Donating vaccines is an encouraging sign.

 

Do you believe the current pandemic will encourage a more global view of public health concerns and their associated impact on economies? 

This is a tough question! We have been warned repeatedly about the risks of emerging infectious diseases. But, unfortunately, we did not act to prevent global pandemics from happening. One may hope that we will draw out the right lessons from the current pandemic. However, I am skeptical. For policymakers, the future always seems far away and purely national issues much more pressing than uncertain existential risks.

 

What value did having access to global data add to your study?

As an applied economist, I value excellent data on a novel and interesting issue more than anything else. The GIDEON database allowed me to publish in an excellent journal and, most importantly, carefully model the spatial diffusion of infectious diseases in a globalized world.

 

How would you have gone about collecting the outbreaks data if the GIDEON database did not exist? 

One possibility would have been to exploit the Global Burden of Disease data. However, despite the provider’s best efforts, the reliability of these data remains uncertain, and diseases are aggregated in relatively coarse categories.

 

In your article, you mentioned the GIDEON database is under-exploited – do you believe it could further contribute to the field of Economics and how? 

Infectious diseases have now become a hot topic in Economics. For various reasons, including data availability, the effects of many diseases were neglected. I hope that my use of the GIDEON database will alert researchers to this incredible information source and encourage more epidemiological research.

 

Click here to read the open-access article Spatial dynamics of major infectious diseases outbreaks: A global empirical assessment

 

Did you like this article? Share it on social media!

Check out more of our latest content here

Yellow Fever: Past and Present

1942, Innoculating eggs with yellow fever vaccine. USPHS (United States Public Health Service) Rocky Mountain Laboratory, Hamilton, Montana
Inoculating eggs with yellow fever vaccine, 1942. USPHS (the United States Public Health Service) Rocky Mountain Laboratory, Hamilton, Montana. Photographer: John Vachon

 

written by Dr. Jaclynn Moskow

What is Yellow Fever?

The yellow fever virus, a flavivirus, is transmitted via the bites of various mosquito species. The disease has an average incubation period of 3 to 6 days. The clinical presentation of yellow fever can vary greatly, ranging from a self-limited flu-like illness to overwhelming hemorrhagic fever – with a case fatality rate of 50%. Approximately 55% of yellow fever infections are asymptomatic, 33% are categorized as mild, and 12% severe (1).

Diagram of Symptoms of Yellow fever patient

Yellow fever generally manifests with the acute onset of fever, headache, backache, myalgia, and vomiting. Conjunctival infection may be seen, accompanied by facial flushing, relative bradycardia (Faget’s sign), and leukopenia. In some cases, fever and other symptoms may remit for a few hours to several days. Upon return of symptoms, icteric hepatitis and a hemorrhagic diathesis may follow with epistaxis, bleeding from the gums and gastrointestinal tract, and petechial and purpuric hemorrhages. Weakness, prostration, protracted vomiting, and albuminuria may also be noted. At this stage, patients will experience renal failure, myocardial dysfunction, necro-hemorrhagic pancreatitis, and seizures.

Yellow fever has a case fatality rate of 10 to 60% within 7 days of disease onset (1).

 

 

The Origin and Spread of Yellow Fever

Phylogenetic analyses indicate that yellow fever originated in Africa within the last 1,500 years. Its spread to the Americas coincided with the trans-Atlantic slave trade that began during the 16th century. It is likely that mosquitoes carrying yellow fever were imported into the Americas via slave ships (2). Significant outbreaks followed as the virus was introduced into populations with no pre-existing immunity. During the 18th and 19th centuries, approximately 25 major outbreaks claimed the lives of hundreds of thousands in New York City, Philadelphia, Baltimore, and New Orleans (3). Yellow fever also arrived in Europe during this time, with notable outbreaks occurring at Spanish, Portuguese, French, and British seaports (4).

It is estimated that for every soldier who died in battle during the Spanish-American War, 13 died of yellow fever (5). Yellow fever also killed many thousands during the construction of the Panama Canal. 

William C. Gorgas (1854-1920), on the site of Panama Canal construction.
William C. Gorgas (1854-1920), on the site of Panama Canal construction. As a U.S. Army surgeon during the Spanish American War, he established methods for eradicating mosquitoes hence reducing yellow fever and malaria among soldiers in Cuba. In 1904 he applied these techniques to control disease among the Panama Canal workers. Ca. 1910.

 

 

Development of a Vaccine for Yellow Fever

USA - CIRCA 1940: A stamp printed in USA shows portrait of Dr. Walter Reed, series Scientists, circa 1940

Early attempts to develop a vaccine for yellow fever resulted in the deaths of several test subjects and researchers. In 1900, a team led by Major Walter Reed traveled to Cuba to study the disease. At this point, the medical community was largely dismissive of the theory that mosquitos were the vectors of transmission for yellow fever. Working under the assumption that the mosquito theory was indeed incorrect, Reed’s team began experimenting with mosquitos and volunteers. After receiving criticism about using human test subjects, some team members decided to instead experiment on themselves. Unfortunately, this resulted in the death of physician-scientist Dr. Jesse Lazear – but with his death, the mosquito theory began to gain acceptance (6). 

Despite the death of Dr. Lazear, yellow fever research on human test subjects continued. The Reed team conducted a second and third set of mosquito experiments, offering financial compensation in the form of gold to study participants (6). After learning that none of these latest Reed study participants had died, Cuban physician Dr. John Guiteras began his own experiments. Unfortunately, three of his 42 test subjects succumbed to the illness, and with this, yellow fever research in Cuba came to a halt (7).

Subsequent efforts to control yellow fever centered on reducing mosquito populations as opposed to vaccine development, until 1918 when the Rockefeller Foundation began conducting yellow fever research. Within a year, Japanese scientist Dr. Hideyo Noguchi, who was working with the Foundation, announced that he had successfully developed a vaccine. Individuals in the United States, Latin America, and the French African colonies began receiving his vaccine, but the legitimacy of the studies leading to its development were soon called into question, and ultimately the vaccine was pulled (7).

The Rockefeller Foundation continued its efforts, and in 1925, they sent investigators to Lagos to determine if the African and South American diseases were caused by the same pathogen. Unfortunately, this trip resulted in three more investigators contracting and dying from yellow fever, including Dr. Noguchi. Nonetheless, the Rockefeller Foundation persisted, and a few years later, another candidate vaccine was developed – this time from efforts led by Dr. Max Theiler (7).

Despite the history of physician deaths related to yellow fever experimentation, Brazilian physician Dr. Bruce Wilson volunteered to receive the first dose of the Theiler vaccine. It was designated a success, and mass production began. Soon after, the Pasteur Institute developed their own vaccine, and for the next several years, the Rockefeller Foundation vaccine was used in the West as well as in England, and the Pasteur Institute vaccine used in France and its African colonies (7).

During World War II, the Rockefeller Foundation vaccine was given to almost all US soldiers. Unfortunately, the vaccine contained blood serum, and vaccination efforts resulted in approximately 330,000 soldiers contracting hepatitis B virus infection (8). Blood serum was subsequently removed as a component of the vaccine, and in 1953 a yellow fever vaccine was licensed for civilian use in the US (9). Use of the Pasteur Institute vaccine eventually ceased due to cases of postvaccinal encephalitis, but a variant of the Rockefeller foundation vaccine is still used today. Dr. Theiler received the Nobel Prize in Physiology or Medicine for his critical role in its development.

 

Yellow Fever in 2021

Yellow fever vaccination est. coverage 1980 - 2019

Today, the Centers for Disease Control and Prevention (CDC) recommends vaccination against yellow fever for individuals 9 months and older and who are traveling to or living in areas at risk in Africa and South America (10). It is a live attenuated vaccine, and thus contraindicated in patients who are immunocompromised. The vaccine is highly effective, with a median seroconversion rate of 99% (range 81–100%) in clinical trials (11).

Yellow fever is currently estimated to affect 200,000 people each year, resulting in 30,000 deaths, with 90% of cases occurring in Africa (12). Recent outbreaks have occurred in Brazil, Angola, Nigeria, and the Democratic Rep. of Congo. If you have a GIDEON account, click here to explore the Yellow Fever outbreak map. There are ongoing efforts to expand accessibility to the vaccine in these regions, as well as to implement additional vector control programs. 

The last outbreak of Yellow Fever in the United States occurred in 1905 (13). Yellow fever outbreaks ceased in Europe after World War II, when, for unknown reasons, the Aedes aegypti mosquito disappeared (14).

The absence of yellow fever in Asia is not fully understood. Some have speculated that differences in mosquito species may play a role. Another theory is that there may be a cross-immunity between yellow fever and other flaviviruses endemic to Asia, such as dengue fever. A third theory is that yellow fever has simply never been introduced into Asia (2).

 

 

 

Did you like this article? Share it on social media!

Check out more of our latest content here

 

References

(1) “Yellow fever”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/yellow-fever-12650

(2) Cathey and J. Marr, “Yellow fever, Asia and the East African slave trade”, Transactions of the Royal Society of Tropical Medicine and Hygiene, vol. 108, no. 5, pp. 252-257, 2014. Available: 10.1093/trstmh/tru043 

(3) F. Douam and A. Ploss, “Yellow Fever Virus: Knowledge Gaps Impeding the Fight Against an Old Foe”, Trends in Microbiology, vol. 26, no. 11, pp. 913-928, 2018. Available: 10.1016/j.tim.2018.05.012 

(4) M. Morillon, B. Marfart, and T. Matton, “Yellow fever in Europe in 19th Century”, Ecological Aspects of Past Settlement in Europe. P. Bennike, pp. 211-222, 2002.

(5) Staples, “Yellow Fever: 100 Years of Discovery”, JAMA, vol. 300, no. 8, p. 960, 2008. Available: 10.1001/jama.300.8.960 

(6) “Politics of Participation: Walter Reed’s Yellow-Fever Experiments”, AMA Journal of Ethics, vol. 11, no. 4, pp. 326-330, 2009. Available: 10.1001/virtualmentor.2009.11.4.mhst1-0904

(7) J. Frierson. “The yellow fever vaccine: a history”, Yale J Biol Med, vol. 83, no. 2, pp. 77-85, 2010

(8) M. Furmanski. “Unlicensed vaccines and bioweapon defense in World War II”, JAMA, vol. 282, no. 9, p. 822, 1999

(9) “Historic Dates and Events Related to Vaccines and Immunization”, Immunize.org, 2021. [Online]. Available: https://www.immunize.org/timeline/

(10)”Yellow Fever Vaccine Recommendations”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Vector-Borne Diseases (DVBD), 2021. [Online]. Available: https://www.cdc.gov/yellowfever/vaccine/vaccine-recommendations.html

(11) J. Staples, A. Barrett, A. Wilder-Smith and J. Hombach, “Review of data and knowledge gaps regarding yellow fever vaccine-induced immunity and duration of protection”, npj Vaccines, vol. 5, no. 1, 2020. Available: 10.1038/s41541-020-0205-6 

(12) “Yellow Fever”, Centers for Disease Control and Prevention, Global Health, 2018. [Online]. Available: https://www.cdc.gov/globalhealth/newsroom/topics/yellowfever/index.html

(13) K. Patterson, “Yellow fever epidemics and mortality in the United States, 1693–1905”, Social Science & Medicine, vol. 34, no. 8, pp. 855-865, 1992. Available: 10.1016/0277-9536(92)90255-o 

(14) “Facts about yellow fever”, European Centre for Disease Prevention and Control, 2021. [Online]. Available: https://www.ecdc.europa.eu/en/yellow-fever/facts

 

 

‘It’s not just COVID-19’ – Dr. Berger on Outbreak News Today podcast

HazMat team in protective suits decontaminating public transport, bus interior during virus outbreak

The global pandemic caused by COVID-19 has rightly taken center stage in media and scientific journals but overshadowed other concerning outbreaks that could do with some attention. GIDEON co-founder Dr. Stephen A. Berger has been speaking with Outbreak News Today to discuss the diseases that are flying under the radar in the media but are still being tracked and reported by GIDEON. 

Listen to the podcast or watch a video recording here.

In 2020, significant outbreaks of Cholera in Yemen, Dengue in Brazil, and neighboring South American countries have been recorded in addition to the COVID-19 pandemic. Numerous diseases such as Ebola, Lassa fever, Chikungunya, Plague, and Monkeypox have broken out in regions of Africa and Asia in recent years as well. Ebola and Monkeypox have proved a persistent threat in the Democratic Republic of Congo, with thousands of cases in the last couple of years alone. Meanwhile, Lassa fever cases in Nigeria in 2020 were the highest recorded by any country in history (nearly 7,000). The disease spreads through rodents, leaving many of its surviving victims deaf.

These and other diseases have historically been considered tropical or exotic and don’t trouble the western population too much, however, the spread of COVID-19 has proven that diseases can and will spread given the opportunity. For instance, Monkeypox, Plague, and West Nile Fever have all had outbreaks within the US in the past. 

Tune in to Outbreak News Today and hear from Dr. Berger and Robert Herriman on this timely subject.

Haven’t got a GIDEON account yet? Sign up for a free trial here.

 

Did you like this article? Share it on social media!

Check out more of our latest content here

21st century outbreaks

21st century outbreaks infographic, displaying top 10 diseases with the most outbreak cases between 2001-2020

 

Which diseases have generated the highest number of cases from outbreaks during the first two decades of the 21st century?  In this blog, we can use GIDEON’s data to find out.

‘Disease outbreak’ is a scary term for many, but every year we suffer dozens, if not hundreds, of localized and international disease outbreaks across the world. While these outbreaks are always significant to those affected, they rarely generate headlines,  and can sometimes go unnoticed outside of the Healthcare Industry.

An “outbreak” is often defined as an increase in case numbers for a particular disease in a defined place and time. Outbreaks can evolve into pandemics (such as with COVID-19) or consist of an isolated cluster of cases, especially for rare and less-communicable diseases, and can persist for years and even decades.

GIDEON collects information on all cases of Infectious Disease worldwide, and much of this effort involves gathering data on outbreaks. The following list has been created using these data, assessing all outbreaks in excess of 500 cases reported from January 2001 to November 2020 – from the GIDEON database of 361 diseases and 233 countries and territories.

  1. Hand, foot & mouth disease (Enterovirus infection) – 2.9+ million outbreak cases

Prominent in Asia, especially over the last 10 years, the most significant outbreaks occurred in 2016 and 2017 – accounting for over 2 million out of total cases. The disease typically affects children, causing a distinctive rash, fever, and nausea (not to be confused with foot-and-mouth disease, which generally only affects livestock).

  1. Viral Conjunctivitis – 4.3+ million outbreak cases

Many outbreaks of this disease were recorded across Asia and South America, the most significant of which was in South Korea in 2002. The latter outbreak resulted in more than 1 million cases. Brazil has also suffered repeated outbreaks, with 10,000 to 100,000 cases reported throughout this period. Often linked with upper respiratory diseases, viral conjunctivitis is also referred to as a ‘pink eye’ due to its principal symptom.

  1. Measles – 5.4+ million outbreak cases

Surprisingly, measles has been one of the most common causes of outbreaks into the 21st century, involving much of the world.  The most notable of these outbreaks occurred in 2019, with nearly 1.5 million cases reported across 50 countries. The disease is best known for its distinctive combination of fever, cough, and a florid rash.

  1. Viral Meningitis – 5.4+ million outbreak cases

While the bacterial variant of the disease is typically associated with large outbreaks in sub-Saharan Africa (a region known as the ‘meningitis belt’), viral meningitis outbreaks are far more common.  Unusually large outbreaks have been reported in China, often affecting neighboring countries as well. Over 4.5 million cases were reported in the region between 2008 and 2012.  Viral meningitis is associated with a stiff neck, headaches, and high fever. Fortunately, rates of fatal viral meningitis have been steadily decreasing for a number of years.

  1. Chikungunya – 9.7+ million outbreak cases

Sometimes mistaken for Dengue or Zika, Chikungunya was most active in the Americas region in recent years.  Even the United States has reported local transmission, which South American countries have experienced hundreds of thousands of Chikungunya cases. Joint pain, high fever, and a rash are the characteristic symptoms, with headaches, chronic pain, and insomnia appearing in later stages of the disease.

  1. Viral Gastroenteritis – 10.2+ million outbreak cases

This entry is a bit of an anomaly here since the vast majority of cases were associated with a single outbreak. In 2006, viral gastroenteritis in Japan was caused by Norovirus, with no less than 10 million cases, – impacting the entire country. Symptoms include diarrhea and/or vomiting, accompanied by abdominal cramps and fever.

  1. Cholera – 12.8+ million outbreak cases

Cholera is an ancient disease that continues to produce regular and significant outbreaks, with case numbers in the 100,000s almost every year. A recent large outbreak that began in 2016 in Yemen, continues to this date – already totaling more than 2.4 million cases. The disease causes severe diarrhea and vomiting, resulting in extreme loss of fluids that can turn a patient’s skin to a bluish-gray color – as they succumb to dehydration. 

  1. Dengue – 26.0+ million outbreak cases

The number of Dengue outbreaks has been increasing in recent years, with cases reaching almost 5 million in 2019 alone. Brazil has experienced major difficulties with this disease, as have neighboring countries, and much of Asia and Africa. Dengue is characterized by high fever, vomiting, headaches, musculoskeletal pain, and a characteristic rash. 

  1. Malaria – 27.7+ million outbreak cases

This mosquito-borne disease typically causes fever, headache, fatigue, and vomiting, but can be complicated by seizures, coma, multi-organ failure, and death in severe cases. Malaria outbreaks have been somewhat less frequent than other diseases on our list over the  21st century; however, the severity and impact of malaria outbreaks are relatively high.  Two major outbreaks of over 8 million cases each have occurred during the past four years. This is not to downplay the overall burden of disease, which the World Health Organization estimated to be as high as 229 million cases in 2019 alone.

Graph of malaria cases worldwide 1973 - today, GIDEON
Malaria cases worldwide 1973 – today, GIDEON

 

 

  1. COVID-19 – 64.5+ million outbreak cases (at the time of writing)

A disease which did not even exist until eleven months ago – is at the top of our list.  The growing number of cases and deaths have made “COVID-19” the most commonly used word used by mankind.  The disease can have a wide range of symptoms but commonly causes coughing, fever, loss of smell and taste, and breathing difficulty. Elderly individuals and those with pre-existing conditions are particularly at risk of developing complications. Even with a vaccine available in the next few months, we must all remain cautious and follow safety measures at all times. 

 

Stay healthy, stay safe!

 

Did you like this article? Share it on social media!

Check out more of our latest content here

Hepatitis A in the United States

Liver Infection with hepatitis viruses - 3d illustration

 

Few Americans are aware of a major epidemic that has taken hold of large areas of their country in recent years – by a disease that is easily diagnosed and prevented. Sadly, public – and even professional interest in these events have been overshadowed by COVID-19.   

AN UPTICK IN CASES

Hepatitis A had been largely under control until three years ago and can be easily prevented through the use of a safe and effective vaccine. 

From January 2017 to January 2019, at least 26 separate outbreaks were reported, to a total of 11,628 cases and 99 deaths, nationwide. Homeless individuals and users of illicit drugs accounted for a large percentage of these patients. 

The graph below shows that the number of reported cases, which had been declining steadily since 1997, has taken a dramatic upturn during the current epidemic. 

 

Hepatitis A cases in the United States, 1947 - today
Hepatitis A cases in the United States, 1947 – today

 

As of September 2020, more than 1,000 cases have now been reported in each of seven states: Florida, Georgia, Indiana, Kentucky, Ohio, Tennessee, and West Virginia. Indeed, the total number of cases reported since the arrival of COVID-19 in the United States has reached 6,650 (to October 10, 2020)  – a major concern to public health specialists.

 

WHAT ARE THE SYMPTOMS?

Hepatitis A is a highly contagious disease that affects the liver. Infection may cause symptoms such as vomiting, jaundice, anorexia, dark urine, and light stools, occasionally accompanied by rash or arthritis. Symptoms normally persist between two to eight weeks, although the illness may last longer and be more severe in patients with underlying conditions.

The case-fatality rate of Hepatitis A ranges from 0.15% to 2.7%, with children faring better than adults.

 

SUPPORTIVE THERAPY IS THE ONLY TREATMENT

At the time of writing, there is no known cure for Hepatitis A. To speed up recovery, it is recommended that patients get plenty of rest and avoid substances that may have adverse effects on the liver, such as alcoholic beverages and certain medications.

 

WHAT IS THE DIFFERENCE BETWEEN HEPATITIS A, B, AND C?

Even though there is no drug therapy against Hepatitis A, it is less dangerous than Hepatitis B and C.

While most Hepatitis A patients recover with lifelong immunity to the disease, Hepatitis B and C may ‘reappear’ in the form of hepatic cirrhosis or hepatocellular carcinoma years after the acute illness. 

Hepatitis B is responsible for 60% to 80% of the world’s primary liver cancer cases. Thankfully, its rates continue to decline in  the United States:

Hepatitis B cases in the United States, 1966 - today graph
Hepatitis B cases in the United States, 1966 – today

 

The mode of transmission also differs among the three viruses. HepA is transmitted via the fecal-oral route, HepB, and HepC through the exchange of infected bodily fluids. 

As of 1998, injecting-drug abuse accounts for 60% of Hepatitis C transmission in the United States:

Hepatitis C cases in the United States, 1992 - today graph
Hepatitis C cases in the United States, 1992 – today

 

Did you like this article? Share it on social media!

Check out more of our latest content here

Interested in learning more about this disease? Get our 2020 eBook on the disease at a 20% discount here.

“Under the radar” – Ongoing Lassa Fever Outbreak

By Dr. Stephen A. Berger

Stethoscope on Africa map
Nigeria is battling the largest recorded Lassa Fever outbreak to-date

 

Lassa Fever in Nigeria is a paradigm for Infectious Disease outbreaks that continue to threaten massive populations “under the radar” during the COVID-19 pandemic. As of October 3, 2020, a total of 1,112 fatal cases of COVID-19 had been reported in Nigeria.

In terms of population size, the statistical likelihood of dying from this disease in Nigeria – or in Singapore – is exactly the same. But then…nobody in Singapore is dying these days from Lassa Fever.    

WHAT IS LASSA FEVER?

The disease was first recognized in 1969, in northeastern Nigeria. The virus is acquired from African rodents and their secretions, primarily the Multimammate rat (Mastomys natalensis) which is its natural reservoir. A secondary person-to-person transmission can occur through contact with infected bodily fluids.

The illness is characterized by fever, pharyngitis, headache, chest pain, and diarrhea. 

Leukopenia, proteinuria, and hepatic dysfunction may also be present. Permanent hearing loss is common – indeed, this disease is the most common cause of acquired deafness in West Africa. Reported case-fatality rates range between 15-25%.

Multimammate rat (Mastomys natalensis)
Multimammate rat (Mastomys natalensis), a reservoir of Lassa Fever

DISTRIBUTION

It is estimated that as many as 500,000 individuals are infected in West Africa each year, resulting in 5,000 deaths. During the past 50 years, at least 88 travelers have returned home to other countries with this disease – including 11 importations into the United States. 

An ongoing outbreak of Lassa Fever continues in Nigeria well into 2020 – with 5,527 cases (222 fatal) reported as of August 16…all against the background of COVID-19.

Lassa Fever outbreaks map 2018-2020
Recent outbreaks map, 2018-2020, GIDEON

 

Did you like this article? Share it on social media!

Find more great content here

Want to learn more? We’ve got the eBook for you! Check out the 2020 edition of  Lassa and Lujo Fevers: Global Status

Brucellosis – how dangerous is it?

Set of different dairy products isolated on white
Brucellosis is most frequently transmitted via unpasteurized dairy products

 

Zoonotic diseases seem to be keeping the world on its toes. What is the disease responsible for the latest outbreak in China and what is its pathogenic potential?

Not the next COVID-19

Brucellosis is a category B bioterror disease, as classed by CDC. While it is one of the most important zoonotic diseases worldwide, brucellosis has limited pandemic potential, since human-to-human transmission is sporadic and occurs via blood, sexual exposure, or breastfeeding. 

63% of cross-border events since 1965 were directly linked to the consumption of unpasteurized dairy products. The largest ever reported outbreak took place in the province of Ghardaia, Algeria, in 2016. During that time, 819 cases were recorded – health authorities suspected consumption of raw milk and a popular traditional cheese “Kamaria” may have been to blame. Epizootics (outbreaks among animals) can be much larger.  Over 40,000 cattle acquired the disease during an outbreak in Spain in 2010. 

 

Brucellosis outbreaks and distribution map, 1938 - 2019
Brucellosis outbreaks and distribution map, 1938 – 2019

 

What are the symptoms of Brucellosis?

Initial symptoms include fever, sweats, and pain in muscles and joints;  while protracted infections may involve the heart valves, liver, or testicles.

Occupational hazard

The outbreak in China occurred among biopharmaceutical plant workers; and several prior disease clusters have involved workers in hospital laboratories.  For this reason, individuals working with Brucella must be especially careful when handling this pathogen.

For instance, in 2007, a biodefence laboratory in the United States was closed after workers were exposed to two bioterror agents: Brucella (agent of Brucellosis) and Coxiella burnetii (agent of Q fever).  Fortunately, this incident did not result in an actual outbreak. Professionals working in such environments are well-prepared for the possibility of similar scenarios and will likely behave in a way that minimizes any risks to public health. 

Interested in learning more? Check out our ebook Brucellosis: Global Status for the latest epidemiological data, clinical findings, and potential use in bioterrorism. The ebook includes 175 graphs and 1,977 references. 

Check out our latest content here

Estimating the True Case-Fatality Rate of COVID-19

For several months, we have been inundated by reports summarizing incidence and mortality data for COVID-19, on both the national and global level. In a previous ProMED post I cautioned that “reported cases” cannot be equated with “total cases” without inclusion of individuals with asymptomatic of sub-clinical infection that do not seek medical care. [1] If a large segment of the population is found to be seropositive, we might conclude that the true case-fatality ratio of COVID-19 is lower than official data might suggest. A seroprevalence study reported this week seems to provide solid evidence that this is the case. [2]

A national survey of individuals identified IgG antibody toward SARS-CoV-2 in 5.0% of the general population of Spain. At the stated specificity of 100% and sensitivity of 98%, the true seropositivity may be estimated at 5.15%. Although factors which determine seroprevalence rates in Spain need not apply to other countries, the following chart extrapolates the potential impact of a 5.15% population seroprevalence on case-fatality data from high-incidence countries in the European Region, United States and China. [3]

The impact of future SARS-CoV-2 seroprevalence surveys will largely depend in the quality of the test itself, the duration of immunity and protective role of the antibody, possible emergence of newer strains of coronavirus, and other factors. In any event, additional seroprevalence data will play a key role in planning our response to this pandemic going forward.

COVID-19 Reported vs. Estimated cases

Country Reported cases % of population Reported Deaths CFR (%)* Estimated cases** Estimated CFR (%)***
Belgium 55,280 0.48% 9,052 16.4 596,548 1.52
China 82,947 0.0058% 4,634 5.6 74,125,174 0.0063
France 179,569 0.28% 28,108 15.7 3,360,686 1.14
Germany 176,651 0.21% 8,049 4.6 4,313,197 0.19
Israel 16,617 0.19% 272 1.6 444,866 0.061
Italy 225,435 0.37% 31,908 14.1 3,114,329 1.02
Spain 277,719 0.59% 27,650 10 2,407,759 1.14
U.K. 243,695 0.35% 34,636 14.3 3,493,878 0.99
U.S.A 1,527,664 0.46% 90,978 6 17,034,349 0.53

* CFR = deaths / cases X 100
** True number of cases based on population seroprevalence of 5.15%
*** Adjusted CFR = deaths / estimated true cases X 100

References

  1. ProMED – What’s the denominator 20200228.7035438
  2. ProMED – Spain: seroprevalence study 20200516.7342334
  3. https://www.worldometers.info/coronavirus/ (status as of May 17)

Is it Safe to Go Back to the Gym? Dr. Berger talks to Shape.com

Illustration of two females exercising in a gym

Many states are relaxing their stay-at-home guidelines, which includes opening up fitness facilities to the public again.  Most must operate under a limited capacity, enhanced cleaning and sanitation practices, and use signs and floor markers to ensure social distancing. But the big question is whether it’s safe to go back? Experts warn social distancing may not be so easy at a gym.

“A gym is just another venue in which disease can be passed from person to person, and the risk of contracting COVID-19 might increase there, where group sports and games require close personal contact,” our co-founder and infectious disease specialist, Dr. Stephen Berger explained to Shape.com

“The fact that you might be young and healthy won’t affect your chance of becoming infected; it will really only increase your chances of surviving an infection without severe or fatal consequences.”

Similarly, if you’re in a region where local officials are mandating or strongly urging residents to wear face masks or other facial coverings in public, the gym is not exempt from those guidelines, notes Dr. Berger.

You can read the entire article here.

And don’t forget to follow us on Twitter, Facebook, and LinkedIn. We’ve got exciting updates about our new interface!

GIDEON Sign In