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Archive for the ‘General’ Category

Reviewing Fungal Infections

by Dr. Jaclynn Moskow

Candida auris fungi, emerging multidrug resistant fungus, agent of fungal infection
Candida auris, an emerging multidrug-resistant fungus

 

Fungi are similar in many ways to bacteria – both have a cell nucleus and complex cell walls. Unlike bacteria, species of fungi include both single-celled organisms (yeasts) and multicellular forms (molds). Molds resemble plants and often consist of filaments, spores, root structures, etc. Fungal infections (mycoses) include candidiasis, dermatophytosis, blastomycosis, coccidioidomycosis, histoplasmosis, cryptococcosis, paracoccidioidomycosis, aspergillosis, zygomycosis, and pneumocystosis.

 

Candidiasis

Candidiasis refers to infections caused by yeasts of the genus Candida. Candida is the most common cause of fungal infections worldwide; and is part of the normal flora of the mouth, GI tract, vagina, and skin. Candidiasis occurs when an imbalance in the amount of Candida in these areas results in signs and symptoms of inflammation, or when Candida colonizes parts of the body in which it is not normally present. All forms of candidiasis are more common in individuals who are immunocompromised. 

Vulvovaginal candidiasis fungal infection, commonly referred to as a “yeast infection,” is estimated to affect 70-75% of women at least once during their lifetimes (1). Symptoms may include itching, burning, soreness, redness, swelling, pain during intercourse or urination, and a thick, white discharge that is usually odorless and may resemble cottage cheese. Factors that predispose to vulvovaginal candidiasis include the use of antibiotics, douches, and other vaginal products, diabetes, hormonal changes such as those seen with pregnancy and menopause, contraceptives, immune deficiency, including HIV / AIDS, and certain genetic factors. A variety of topical and systemic azole agents can be used for treatment.

Oropharyngeal candidiasis commonly referred to as “thrush,” occurs from Candida overgrowth on the lining of the mouth, tongue, gums, tonsils, and lips. The condition may cause visible white or yellow patches, soreness, an unpleasant taste, and occasionally a “cotton-like sensation.” It is much more common in infants and toddlers than in adults. Predisposing factors in adults include smoking, dentures, antibiotic and corticosteroid use, and hormonal changes. 80-90% of HIV patients will experience oropharyngeal candidiasis (2). Proper dental hygiene may help protect against oropharyngeal candidiasis. Various azole mouthwashes, gels, and lozenges can be used for treatment, as well as oral antifungal medications.

Common sites of cutaneous candidiasis include the axilla (armpit), the area under the breast, the groin region, the intergluteal cleft, and on the hands and feet. Candida is a common cause of “diaper rash.”

Invasive candidiasis (“deep candidiasis”) occurs when Candida affects the bloodstream, heart, brain, eyes, bones, or other organs. It may occur in patients that are immunocompromised, or as a result of fungal infection introduced by vascular lines, prosthetic cardiac valves, and urinary catheters. Systemic symptoms may result, including fever, chills, pain, hypotension, and neurological deficits. The condition can be fatal. One strain, in particular, Candida auris, poses a threat in hospitals, as it is often multidrug-resistant and difficult to identify using standard laboratory methods (3).

 

Dermatophytosis

Dermatophytosis (“tinea”) is a fungal infection of keratinized tissue, including the skin, hair, and nails. Fungal causes include Ascomycota, Euascomycetes, Onygenales: Epidermophyton, Microsporum, Trichophyton, Trichosporon spp., and Arthroderma (4). Dermatophytosis is contracted by contact with infected humans or animals, or contact with contaminated objects, flooring, or soil.

Trichophyton mentagrophytes - an agent of fungal infection
Fungus Trichophyton mentagrophytes

 

The nomenclature of these conditions derives from the body region that is affected. For example, Tinea manuum is a dermatophyte infection of the hands, while Tinea barbae is an infection of the beard or mustache. Tinea pedis affects the feet, Tinea unguium the nails, Tinea cruris the groin, Tinea corporis the trunk, Tinea capitis the scalp, and Tinea faciei the non-bearded area of the face. 

Tinea corporis is commonly referred to as “ringworm.” It presents as a red, annular, scaly patch, often with central clearing. The condition is usually pruritic and is very common – especially among children. High rates are seen in Africa, India, and urban areas of the Americas (5). A common source of adult infection is through handling puppies and kittens. A wide variety of creams, ointments, gels, and sprays are available for treatment.

Tinea pedis is commonly referred to as “athlete’s foot”; and is the most common form of dermatophytosis in adults (6). The condition can cause itching, stinging, and burning of the feet – often with redness, blisters, and peeling. Tinea pedis is often acquired from wet floor surfaces such as showers, locker rooms, and pool areas. Wearing foot protection in these areas can help prevent transmission. 

The same fungal species that cause Tinea pedis can also cause Tinea cruris, commonly known as “jock itch.” Tinea cruris presents as a red, pruritic, and often annular rash in the crease of the groin. The condition may spread to the upper thigh in a “half-moon” shape. The condition can be acquired by sharing contaminated towels or clothing. Both Tinea pedis and Tinea cruris usually respond well to topical antifungals.

 

Endemic Mycoses

Endemic mycoses refer to a diverse group of fungal infections found in distinct geographical regions. They can cause significant morbidity and mortality in immunocompromised individuals, and may also affect healthy people. 

Blastomycosis is caused by the fungus Blastomyces. It mainly affects people living in regions of the United States and Canada surrounding the Ohio and Mississippi River valleys and the Great Lakes (7). Blastomycosis is acquired through inhalation of spores, often after participating in activities that disturb the soil. Symptoms are “flu-like” and may include fever, fatigue, muscle aches, night sweats, and cough. A chronic disease may affect the lungs, skin, bones, joints, genitourinary tract, or central nervous system. Amphotericin B is the treatment of choice.

Coccidioidomycosis (“Valley Fever”) is caused by Coccidioides immitis and Coccidioides posadasii. The condition is found in the Southwestern United States and parts of Mexico and Central and South America. Like blastomycosis, coccidioidomycosis follows the inhalation of spores from the soil. Symptoms are similar to coccidioidomycosis and are flu-like. A rash on the upper body or legs is commonly encountered. Most people with coccidioidomycosis improve without treatment, but fluconazole and similar antifungals can be used (8).

Fungus Coccidioides immitis, saprophytic stage, 3D illustration showing fungal arthroconidia. Pathogenic fungi that reside in soil and can cause fungal infection Coccidioidomycosis, or Valley fever
Coccidioides immitis, an agent of fungal infection Coccidioidomycosis (aka Valley fever), saprophytic stage.

 

Histoplasmosis, caused by Histoplasma, is acquired by inhaling spores – usually from soil containing bird- or bat-droppings.  The condition is found in the Ohio and Mississippi River valleys and parts of Central and South America, Africa, Asia, and Australia (9).  Histoplasmosis is also characterized by a flu-like illness and is usually self-limiting. 

Cryptococcosis is caused by various species of Cryptococcus, yeasts that are found in the soil and on certain trees. Cryptococcus gattii is found in California, Oregon, Washington, Canada, Australia, Papua New Guinea, and South America (10). Cryptococcus neoformans is found in all countries. Cryptococcus is often associated with pneumonia or meningitis. The current global incidence is estimated at 1 million cases per year, with 50% mortality (11). Most of these cases occur in individuals with HIV / AIDS. Treatment consists of Amphotericin B and Flucytosine, followed by Fluconazole.

Paracoccidioidomycosis is caused by Paracoccidioides, found in parts of Central and South America (12). It can cause lesions in the mouth and throat, rash, lymphadenopathy, fever, cough, and hepatosplenomegaly. Talaromycosis, formally known as sporotrichosis, is an endemic mycosis caused by Talaromyces marneffei and other species. The condition is found in Southeast Asia, Southern China, and Eastern India (13). Clinical manifestations include fever, cough, lymphadenopathy, hepatosplenomegaly, diarrhea, and abdominal pain.

 

Mold Infections

Most people inhale mold spores every day without becoming ill, but occasionally severe disease can result. Infection by Aspergillus (aspergillosis) may present as an allergic reaction. The fungus can also cause infection of the sinuses and lungs. Formation of “fungal ball” (aspergillomas) may occur in patients with pre-existing lung diseases. Aspergillus can also infect the eyes, skin, cardiac valves, brain, gastrointestinal tract, and genitourinary tract. Treatment options include Voriconazole, Amphotericin B, and Isavuconazole (14).

Aspergillus (mold) under the microscopic view. Aspergillus is an agent of fungal infection.
Aspergillus spp. under a microscope

 

Zygomycosis (“mucormycosis”) is caused by a group of molds called Mucormycetes. This fungal infection is commonly associated with hyperglycemia, metabolic (diabetic, uremic) acidosis, corticosteroid therapy, and neutropenia, transplantation, heroin injection, and administration of deferoxamine (15). Common sites of infection include the paranasal sinuses and contiguous structures, cranial nerves, cerebral arteries, lungs, and skin. Treatment may include intravenous Amphotericin B, followed by oral Posaconazole or Isavuconazole.

Other molds that can cause allergies and infections in humans include Stachybotrys chartarum, Alternaria alternata, Lomentospora prolificans, Scedosporium apiospermum, Cladosporium, and Penicillium.

Pneumocystis jirovecii, an agent of Pneymocystis pneumonia
Pneumocystis jirovecii, an agent of Pneumocystis pneumonia fungal infection

Pneumocystis pneumonia

Pneumocystis pneumonia (PCP) is caused by the fungus Pneumocystis jirovecii.  Until recent years, the organism had been classified as a protozoan parasite. Pneumocystis pneumonia usually occurs in individuals with severe immune suppression, including HIV / AIDS.  Presenting symptoms include shortness of breath, fever, and a nonproductive cough. Extrapulmonary infection is rare but can occur. Treatment options include Sulfamethoxazole / Trimethoprim, Pentamidine, Dapsone + Trimethoprim, Atovaquone, or Primaquine + Clindamycin (16).

 

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References

(1) Sobel JD. Vulvovaginal candidosis. Lancet. 2007 Jun 9;369(9577):1961-71. doi: 10.1016/S0140-6736(07)60917-9.

(2) Patil S, Majumdar B, Sarode SC, Sarode GS, Awan KH. Oropharyngeal Candidosis in HIV-Infected Patients-An Update. Front Microbiol. 2018 May 15;9:980. doi: 10.3389/fmicb.2018.00980.

(3) “General Information about Candida auris”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2019. [Online]. Available: https://www.cdc.gov/fungal/candida-auris/candida-auris-qanda.html

(4)”Dermatophytosis”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/dermatophytosis-10600

(5) M. Handler, “What is the global incidence of tinea capitis (scalp ringworm)?”, Medscape.com, 2020. [Online]. Available: https://www.medscape.com/answers/1091351-36134/what-is-the-global-incidence-of-tinea-capitis-scalp-ringworm

(6) Ilkit M, Durdu M. Tinea pedis: the etiology and global epidemiology of a common fungal infection. Crit Rev Microbiol. 2015;41(3):374-88. doi: 10.3109/1040841X.2013.856853.

(7) “Blastomycosis”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2020. [Online]. Available: https://www.cdc.gov/fungal/diseases/blastomycosis/index.html

(8) “Treatment for Valley Fever (Coccidioidomycosis)”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2019. [Online]. Available: https://www.cdc.gov/fungal/diseases/coccidioidomycosis/treatment.html

(9) “Histoplasmosis”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2020. [Online]. Available: https://www.cdc.gov/fungal/diseases/histoplasmosis/index.html

(10) “C. gattii Infection Statistics”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2020. [Online]. Available: https://www.cdc.gov/fungal/diseases/cryptococcosis-gattii/statistics.html

(11)”Cryptococcosis worldwide distribution”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/cryptococcosis-10530/worldwide

(12) “Paracoccidioidomycosis”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2020. [Online]. Available: https://www.cdc.gov/fungal/diseases/other/paracoccidioidomycosis.html

(13) “Talaromycosis (formerly Penicilliosis)”, Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Foodborne, Waterborne, and Environmental Diseases (DFWED), 2020. [Online]. Available: https://www.cdc.gov/fungal/diseases/other/talaromycosis.html

(14) “Aspergillosis”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/aspergillosis-10140

(15) “Zygomycosis”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/zygomycosis-12670

(16) “Pneumocystis pneumonia”, GIDEON Informatics, Inc, 2021. [Online]. Available: https://app.gideononline.com/explore/diseases/pneumocystis-pneumonia-11850

Listeriosis in the European Union

A recent series of outbreaks in Europe reflects an increasing incidence of listeriosis in the region.  In the following graph I’ve contrasted disease rates per 100,000 in the European Union with those of the United States [1,2] :

 

References:

  1. Berger S. Listeriosis: Global Status, 2018. 128 pages, 108 graphs, 1,203 references. Gideon e-books,  https://www.gideononline.com/ebooks/disease/listeriosis-global-status/
  2. Gideon e-Gideon multi-graph tool,  https://www.gideononline.com/cases/multi-graphs/

Note featured on ProMED

Pathogens Associated with Animal Bites

Gideon www.GideonOnline.com lists 31 species of bacteria which have been associated with human infection following the bites of animals:
– Bacteroides tectus
– Bergeyella zoohelcum
– Bisgaard’s taxon
– Capnocytophaga canimorsus
– Corynebacterium canis
– Capnocytophaga cynodegmi
– Corynebacterium freiburgense
– Corynebacterium kutscheri
– CDC NO-1
– Erysipelothrix rhusiopathiae
– Fusobacterium canifelinum
– Halomonas venusta
– Kingella potus
– Moraxella canis
– Mycobacterium vulneris
– Neisseria animaloris
– Neisseria canis
– Neisseria weaveri
– Neisseria zoodegmatis
– Pasteurella caballi
– Pasteurella canis
– Pasteurella dagmatis
– Pasteurella multocida
– Pasteurella stomatis
– Psychrobacter immobilis
– Spirillum minus
– Staphylococcus intermedius
– Streptobacillus moniliformis
– Vibrio charchariae
– Vibrio harveyi

Although virtually all literature on the subject advocates administration of tetanus prophylaxis following animal bites, few if any cases of bite-associated tetanus have been documented.

Leprosy in the Western Pacific Region

Leprosy data for the Western Pacific Region indicate that disease incidence is highest in the Philippines, Vietnam and China. In the following graph, I have contrasted incidence and prevalence statistics for countries mentioned in the ProMED note, with population-adjusted rates for these same data. [1,2] Note that the numbers of cases per 100,000 population are highest in Micronesia, Kiribati and the Marshall Islands. See graph:

References:
1. Berger SA. Leprosy: Global Status, 2012. 236 pp, 376 graphs, 226 references. Gideon e-books, https://www.gideononline.com/ebooks/disease/leprosy-global-status/
2. Gideon graph tool at https://www.gideononline.com/wp-content/uploads/Gideon-Graphs.pps

Note featured on ProMED

Bye to Mike Homer – a victim of CJD

Mike Homer passed away yesterday from CJD (Creutzfeldt-Jakob disease). CJD is a rare neurological disease, which can be infectious, but wasn’t in this case.

Mike was one of my senior managers at Netscape, who I always held in high regard. I’m saddened by this event and hope this will help accelerate research into a cure for the disease.

Famous People: How They Died in 2008

(In addition to its decision support application dealing with Infectious Diseases, Microbiology and Toxicology, GIDEON Informatics, Inc as part of GIDEON Labs, maintains a second service – www.VIPatients.com – which follows the diseases and deaths of all famous persons throughout history. The user can review all diseases of a specific VIP, or generate a list of famous persons by Profession, Disease, Year – or any combination. The following is based on data generated from the site).

On December 31, the Media will once again recount all of the wars, earthquakes, divorces, births, rapes, sporting records …. Inevitably, a long list of famous persons will have passed on: most “after a long illness,” “suddenly” or “of natural causes.” 427 famous folk died of specified misfortunes in 2008. For the purpose of this research, “famous” is defined as “well recognized by the general public at large.”

(more…)

2008 – A year of new outbreaks and new bugs

Predictably, 2009 will be greeted with endless publications that recount the divorces, disasters, political events, athletic records, and famous deaths of 2008. Sadly, the routine misfortunes which visit most of the world will be largely neglected. Individual countries are burdened by major outbreaks of infectious disease on an almost daily basis, but few people in the West hear of these episodes unless they are sensationalized by the media (Ebola) or are seen as a threat to other developed nations (Avian influenza).

Although the current outbreak of Avian influenza (“bird flu”) began in 2003 and has continued well into 2008, the number of reported cases and deaths has actually been decreasing since, 2006. A total of only 387 cases, and 245 deaths, from this infection, have been reported to date. In other words, the chance of dying from a lightning bolt or scorpion sting in one of the infected countries is far greater than the chance of acquiring bird flu.

During the past year, cases of human disease were reported in only 5 countries – while infection of birds occurred in 23 countries.

Note that the cases appear to occur in waves – first involving Vietnam, then Indonesia, and finally Egypt.

Speaking of Egypt, few realize that a classic disease associated with that country continues to affect many parts of the world. Four countries reported plague outbreaks during 2008: China, Madagascar, Uganda, and the Democratic Republic of Congo.

Does anybody still remember ‘Ebola.’? Ebola became a household word in 1995 when cases in Africa appeared on the backdrop of one or more Hollywood movies about lethal bugs carried to America by villains, monkeys, and other primates. The good news is that no Ebola outbreaks occurred in 2008; though few realize that more cases were reported in Africa during ’07 than during the panic-year of ’95.

The next panic-year in America was 2001 when anthrax evolved into a mail-order disease. In 2008, a man in London died of anthrax acquired from African animal skins used to make drums. Similar cases were reported in Scotland and in New York City in 2006. No fewer than twenty countries reported outbreaks of human (11 countries) or animal anthrax in 2008. As is often the case, these outbreaks occurred in areas of misery and upheaval – Iraq and Zimbabwe.

In fact, Zimbabwe has become a paradigm for epidemics in recent months. As we move into 2009, a massive outbreak of cholera is spreading through the country, with many cases in the capital city and infected refugees spreading the disease into neighboring South Africa. Outbreaks of cholera were officially reported by 37 countries in 2008, while many others reported “severe diarrhea” – a euphemism for cholera, often used by nations that would rather not scare tourists with the “C” word.

For diseases, 2008 was a matter of “business as usual.” Dysentery, salmonellosis, influenza, conjunctivitis, Legionnaire’s disease, Norovirus gastroenteritis, Lyme disease, plague, rabies … simply plague humanity.

The Health establishment once promised us that at least two diseases would be eliminated by the 21st century: Poliomyelitis and Measles. Sadly, outbreaks of both were still reported in 2008. In both cases, safe and effective vaccines are simply not being used in some populations. In contrast, other diseases for which vaccines do not exist will continue to worry us all into 2009 – AIDS, Malaria, Dengue, Hepatitis C, West Nile fever…

Inevitably, each new year heralds the discovery of new diseases and pathogens. Sadly, new antibiotics and vaccines appear at a slower pace. One of the more interesting outbreaks of 2008 involved over 1 million cases of Chikungunya in India, Malaysia, and nearby countries. Chikungunya is caused by a virus spread by mosquitoes and is characterized by fever, rash, and severe inflammation of joints. Inevitably, the disease began to be reported among tourists returning from affected countries (approximately 50 to the United States, and almost 1,000 to France) and ultimately 337 cases acquired in Italy in 2007, as local mosquitoes began to transmit the virus. These events remind us of the entry of West Nile fever into the United States in 1999, and to forebode similar events in years to come.

The good news is that some diseases are disappearing. Cases of leprosy are on the decline, with fewer than 500,000 lepers estimated for the entire planet as of this year. A rather nasty parasite, Dracunculus, incapacitated over 720,000 Africans in 20 countries as recently as 1988; fewer than 10,000 in 9 countries as of 2008. SARS has simply disappeared as a disease, with no cases reported since the outbreak of 2003. Active mass treatment and prevention campaigns continue to reduce the incidence of river blindness, childhood meningitis, tetanus, diphtheria, and some forms of hepatitis.

Interview with GIDEON’s CEO

Steve Stallman recently interviewed Uri Blackman, GIDEON’s CEO, in SCribe magazine, which was mentioned in the Technology Council of Southern California blog. The interview provides some background on the company and the benefit of GIDEON to its users:

What is the main value proposition you offer?
Originally, we focused on compiling the entire world’s data for Infectious Diseases in one easy to use location combined with medical decision support. Now we have taken this to the next level by adding other medical domains on our platform. We help identify the diseases, their global footprints, and provide specific information on treatments. Medical professionals now have one clear source to get the most up to date information, which can change by the minute. This often makes them aware of things they never thought of and helps them make the best decision possible.

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