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Archive for the ‘Outbreaks’ Category

Measles: Correlation of Vaccine Uptake with Disease Rates

The following is a country-by-country analysis of measles reporting trends vs. vaccine uptake.  For purposes of consistency, incidence data and population statistics used to calculate rates per 100,000 will be limited to those published by the World Health Organization (WHO).  Resultant graphs were generated by Gideon and abstracted from the Gideon e-book series [1,2]  True estimates of vaccination update statistics are those published by WHO, in most cases available only since 1980.  Data published by the countries themselves were not used, to avoid possible bias or inconsistency when comparing data among countries. Historical disease data which precede 1980 have also been appended to graphs to further appreciate the impact of vaccination.

The reader will note that in virtually all cases, the presumed impact of vaccine uptake on disease incidence occurs when vaccine uptake exceeds 80%, and again when rates increase beyond 90%.   As such, the few countries which have not achieved 80% uptake, or have consistently reported >90% uptake since 1980 are excluded.  Graphs are not included for countries for which data are not reported, or reported only sporadically.

Individual graphs for 135 countries are presented below in alphabetical order.  In 127 (94%) of these, a clear relationship seems to exist between increasing vaccine uptake and decreasing rates of measles.  In eight cases, temporary “spikes” in disease incidence were reported during years of high vaccine uptake: Japan, Jordan, Republic of Korea, Seychelles, Solomon Islands, South Africa, Sri Lanka and Syria.

I have not attempted to perform a statistical analysis of this phenomenon, and cannot say with certainty that a confounding (third) factor does not exist.  Nevertheless, these graphs appear to indicate a favorable effect of vaccination on measles incidence.

Measles Vaccine Uptake vs. Disease rates (per 100,000)


  1. Gideon e-Gideon multi-graph tool,
  2. Berger S. Measles: Global Status, 2019. 548 pages , 538 graphs , 5,779 references. Gideon e-books,

Leptospirosis in Israel

The following background information on Leptospirosis in Israel is abstracted from Gideon and the Gideon e-book series. [1,2] Primary references are available from the author.

Leptospirosis is most common in agricultural settlements of the Galilee, during the months of June to September.  Reported disease incidence reached a peak of 81 cases in 1962, but have since decreased considerably. 48 cases were reported during 2002 to 2008 – including 20 travel-related cases (15 of these acquired in southeast Asia).  Rates per 100,000 have been comparable to those reported in the United States for the past three decades (see graph) [3]

During 1970 to 1973, the main infecting serovars of Leptospira interrogans were grippotyphosa (41%) and hebdomadis (31%).  Serovars hardjohebdomadis and grippotyphosa accounted for 79% of cases during the 1970’s, and 32% during 1985 to 1999.  Serovar. icterohaemorrhagiae accounted for 2% during the 1970’s, and 29% during 1985 to 1999.

14 fatal cases of leptospirosis were reported during 1954 to 2017, the most recent in 1999.

The following chart summarizes five outbreaks of leptospirosis reported from Israel.


  1. Berger S.  Leptospirosis: Global Status, 2018.  223 pages , 177 graphs , 1,840 references. Gideon e-books,
  2. Berger S. Infectious Diseases of Israel, 2018. 481 pages , 238 graphs , 1,503 references. Gideon e-books,
  3. Gideon e-Gideon multi-graph tool,

Note featured in ProMED


Disease Outbreaks due to Sprouts

As of June, 2018 the Gideon database ( chronicles 22,777 published Infectious Diseases outbreaks.  Sprouts were implicated in 13.4% of outbreaks which specify a disease vehicle (5.2% of salmonellosis outbreaks).  Salmonellae were responsible for 83% of outbreaks associated with sprouts.  The remainder were caused by Escherichia coli, Listeria monocytogenes or Bacillus cereus. [1]


1 Berger S. Gideon Guide to Outbreaks, 2018. 2,011 pages, 5,272 tables, 51,622 references. Gideon e-books,

New Video tutorials for Outbreaks, Surveys and Cross Border Events

Dr. Steve Berger has release new videos to review how to use the Outbreaks, Surveys and Cross Border Events Public Health features of GIDEON.

They are included below:

Norovirus Infection in South Korea

The following background information on Norovirus infection in South Korea was abstracted from Gideon and the Gideon e-book series. [1-3]  A computer-generated parsing program of PubMeD and ProMED identifies 22,521 published Infectious Diseases outbreaks.  735 of these outbreaks specify Norovirus as the disease agent.  South Korea accounts for 0.67% of all outbreaks, and for 1.5% of Norovirus outbreaks.  Details of the individual events are summarized in table 1.

Further analysis of these sources identified 59,774 prevalence / seroprevalence surveys.  745 of these surveys examine the prevalence of viral agents associated with gastroenteritis.  South Korea accounts for 18.6% of all Infectious Disease surveys, and 3.4% of surveys involving viral gastroenteritis. Details of surveys which examine Norovirus prevalence are summarized in table 2.

Primary references are available from the author.


  1. Berger SA. Infectious Diseases of South Korea, 2018. 418 pages, 108 graphs, 2,260 references. Gideon e-books,
  2. Berger SA. Gideon Guide to Outbreaks, 2018. 1,900 pages, 5,246 tables, 50,908 references.
  3. Berger SA. Gideon Guide to Surveys, 2018. 4,028 pages, 10,229 tables, 53,802 references.


Trichinosis from Bear Meat

356 published outbreaks of trichinosis are chronicled by Gideon ( .  Where relevant information is given, bear meat is specified as the food vehicle in 13.6% of these outbreaks – see chart below. [1,2]  (Additional details and primary references are available from Dr. Berger).


  1. Berger SA. Gideon Guide to Outbreaks, 2017. 1818 pages, 5120 tables, 47454 references. Gideon e-books,
  2. Berger SA. Trichinosis: Global Status, 2017. 114 pages, 75 graphs, 1037 references. Gideon e-books,

Note featured in ProMED

Public Health enhancement: Outbreak and Survey tables

Outbreak / Survey tables are new additions to GIDEON. The innovative design allows users to quickly scan and compare outbreaks / surveys according to year, setting, number of cases / deaths, affected population and other parameters. This is the cumulative result of a huge effort to convert over 20,000 outbreaks and 50,000 surveys in GIDEON from text format to a database. Cross border events have also undergone this transformation in Worldwide notes.

GIDEON is the first publication which gathers all infectious disease outbreaks and surveys into a single site – from ancient plagues to last week’s Zika statistics. Now these are much easier to read and analyze.

This is an excellent resource for experts and students in public health:

  • Sorting option allows for meaningful analysis
  • Ideal tool for studying the history of medicine, trends in disease evolution, diseases of all individual countries.
  • The tables can help prepare lecture handouts
  • Updated every few days and constantly evolving.

Sort the outbreaks / surveys by clicking on the top column heading. Additional notes and linked references are displayed where available once you click “Show notes” for all the rows, or click on the year to see the notes for a specific row.


In the following example, data are displayed alphabetically by outbreak setting or region.
Outbreak tables


South Sudan: Unknown Hemorrhagic Illness

Regarding an ongoing outbreak of hemorrhagic illness in South Sudan, a differential diagnosis list generated by Gideon [Global Infectious Disease & Epidemiology Network], includes 2 lesser-known pathogens which have been associated with single small clusters of hemorrhagic fever in Africa: Bas-Congo virus (rhabdovirus) and Lujo virus (arenavirus). In 2008, 4 of 5 patients died of Lujo virus infection in a South African hospital, following transfer of an index patient from Zambia. The following year, 2 of 3 villagers in DR Congo died in an outbreak of Bas Congo virus infection. If tests for other pathogens continue to be negative, these 2 agents might be considered.

Cited on ProMED

Diphtheria in Latvia

Following a regional epidemic during the 1990’s, Latvia has continued to experience a high incidence of diphtheria. [1]  This phenomenon is difficult to explain on the basis of poor vaccine uptake. The following graph compares W.H.O. estimates of vaccination (DPT3) coverage with diphtheria rates reported in Estonia, Latvia and Lithuania. [2]



1. Berger SA. Infectious Diseases of Latvia, 2015. 436 pages, 103 graphs, 1,497 references. Gideon e-books,

2. Berger SA. Diphtheria – Global Status, 2015. 333 pages, 445 graphs, 374 references. Gideon e-books,



Note featured on ProMED


Arthropod-borne Viruses of Senegal

A recent outbreak of suspected viral infection in Kedougou Region ( highlights the complexity of establishing a specific etiological agent in West Africa.  At least twenty arthropod-borne viruses are associated with known or suspected human infection in Senegal.  The following alphabetical list is abstracted from Gideon and the Gideon e-book series [1]   (Primary references are available from Dr. Berger on request)

Bagaza – Bagaza virus has been recovered from mosquitoes in Senegal (Aedes fowleri, Culex neavei, Cx. Poicilipes and Mansonia, Mimomyia hispida, M. lacustris, M. splendens and Aedeomyia africana.

Bangui – Bangui virus was identified in mosquitoes in the Senegal River basin in 1988.

Bunyamwera – Bunyamwera virus has been identified in mosquitoes in the Barkedji region.

Chandipura – Chandipura virus has been identified in mosquitoes in the Barkedji region, and in phlebotomines in the Kedougou district.

Chikungunya – Outbreaks of Chikungunya were reported in Senegal in 1966, 1977, 1982, 1988, 1992, 1996 and 1997.  In 2006, a cluster of six cases in France was reported among travelers returning from Senegal. The virus has been found in a variety of local mosquito species, notably Aedes furcifer-taylori, Ae. luteocephalus, Ae. dalzieli and Stegomyia (Aedes) aegypti. Additional vectors may include Ae. vittatus, Anopheles rufipes and An. coustani.

Dengue – An outbreak of dengue was reported in Senegal during 1927 to 1928; and circulation of the virus was subsequently confirmed in 1974 and during 1999 to 2000. An epizootic among monkeys was reported in 1981; and the first human case was reported in 1983 (from Casamance). Several human and monkey infections were reported in 1990. In 2009, a dengue outbreak (196 cases, 1 fatal) was reported – the first reports of human dengue in Senegal for two decades. Italy reported a case of dengue hemorrhagic fever, imported from Senegal, and cases of dengue fever have been confirmed among French military personnel serving in this country.

Gabek Forest – Gabek Forest virus, a Phlebovirus, has been identified in sandflies (Phlebotomus species) in Senegal (1990 to 1995).

Koutango – Koutango virus (similar to Spondweni virus) has been identified in mosquitoes (Culex neavei) in the Barkedji region.

LeDantec – LeDantec virus is a rhabdovirus which is distinct from the vesicular stomatitis group 1. A single case of infection was reported in Senegal in 1965.

Ngari – Ngari virus has been identified in mosquitoes in the Barkedji region.  Two cases of Ngari virus infection were reported from Dakar,

O’nyong nyong – Although specific data are lacking for Senegal, circulation of O’nyong nyong virus is reported in this region of West Africa.

Rift Valley fever (RVF) – RVF virus was first isolated in West Africa in 1974, from Aedes (Aedimorphus) dalzieli in Senegal. Highest seroprevalence rates are found in the northwest and northcentral regions. Serological studies suggest that the disease was active in Diawara and Bakel (Eastern region) in 1998. Outbreaks were reported among goats, sheep and / or cattle in 2002, 2003, 2013 and 2014.  Carriage by mosquitoes and seroprevalence among sheep in the northern region increased during the 1990’s. Rift Valley virus was identified in mosquitoes in Barkedji in 1993, and re-emerged in 2002. A single isolated case of human Rift Valley fever was confirmed in a school teacher in Kedougou in 2012.

Rift Valley fever virus – seroprevalence surveys:

22.3% of Peul people of the North-central region

15.3% of the population in the Senegal River basin (1995 to 1996)

5% of children born after 1987, vs. 25.3% of the older population in Podor District (1999 publication)

5.2% of individuals in Diawara (1999)

2.9% of small ruminants tested in the Ferlo region (2003)

24.4% of sheep and goats in the Senegal River basin in 1988, 19.3% in 1989

17.2% of ungulates in the Senegal River Basin (1990)

3.8% of wild rodents, notably Rattus rattus, Mastomys huberti, A. niloticus and M. erythroleucus (2000 publication)

Semliki Forest – Semliki Forest virus has been recovered from mosquitoes (Aedes vittatus) and ticks (Rhipicephalus guilhoni) in Senegal.

Tataguine – Antibody toward Tataguine virus is found in 57% of the population.

Usutu – Zoonotic infection by Usutu virus has been identified in Senegal.

Wesselsbron – Seropositive humans were documented in Senegal during 1972 to 1975; and the virus itself has been identified in mosquitoes (Aedes vexans) in the Barkedji region.

West Nile – Seroprevalence rates for West Nile virus of 78.3% to 92% have been reported among horses. Infection of wild birds and dogs has also been identified. Vector mosquito species in this country are thought to include Culex neavei, Cx. tritaeniorhynchus, Cx. modestus, Cx. perfuscus group, Cx. poicilipes, Aedes vexans, Mimomyia hispida, Mi. lacustris, Mi. splendens, Aedeomyia africana and Mansonia uniformis

Yellow fever – Epidemics of yellow fever were reported in Senegal in 1768, 1769, 1778 to 1779 (50 deaths among Caucasians), 1814, 1816, 1828, 1830, 1837, 1840 to 1841, 1844, 1852, 1858, 1863, 1866, 1872, 1900 to 1901 (225 fatal cases) and 1923 to 1927. Aedes furcifer, A. metallicus and A. luteocephalus are involved in the wild vertebrate transmission cycle in this country. Yellow-fever activity among mosquitoes in Senegal has been used to monitor potential human disease in West Africa. Infected mosquitoes were identified during 1976 to 1979, 1983, 1987, 1989, 1990, 1992, 1993 and 2010.  Chronology of recent Yellow fever outbreaks in Senegal:

1965 – 243 cases were reported in Diourbel.

1965 to 1966 – 2,000 to 20,000 cases and 200 to 2,000 deaths were estimated.

1979 – Two French tourists contracted fatal yellow fever in Senegal.

1995 – Cases reported in Ribo-Escale and Guente-Pate Districts (vicinity of Koungheul).

1996 – Highest number of cases for any country (30.2% of the world’s total), including an epidemic centered at Kaffine town. {p 9855398}

2001 – Three cases were reported in Kedougou District (Health Ministry report not included in WHO data).

2002 – An outbreak (78 cases, 11 fatal) was reported – with 18 cases in Diourbel and Ziguinchor regions, and 60 cases in Touba, Mbacke and Bambey districts, Diourbel region; Gossas and Fatick districts, Fatick region; Tambacounda district in Tambacounda region; Louga, Koulda and Dakar regions.

2005 – Activity was reported in Tambacounda region (Goudiri, Kadira)

2010 – Two Senegalese fishermen acquired yellow fever in Gambia.

2011 – Three cases were reported in Kedougou and Saraya Health districts, near the borders with Mali and Guinea Conakry.

Zika – There is evidence for the occurrence of yearly epizootics of Zika virus infection in Senegal. In 2008, two American scientists contracted Zika in the country. Natural infection has been identified in two local primate species, Cercopithecus aethiops and Erythrocebus patas; and in 1.82% of mosquito pools (2011).

Zinga – Zinga virus, a variant of RVF virus, has been identified in humans and mosquitoes in Senegal.



  1. Berger SA. Infectious Diseases of Senegal, 2015. 449 pages, 55 graphs, 1,864 references.  Gideon e-books,