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Archive for the ‘Epidemiology’ Category

Diphtheria in Thailand

Although two fatal cases of diphtheria were recently reported in Thailand [1], rates of this disease have declined dramatically since the 1970’s.  In fact, Thailand can serve as an icon for the effectiveness of vaccination.  In the following graph, I’ve contrasted rates of diphtheria, pertussis and tetanus with WHO estimates of DPT vaccine uptake.  The second graph depicts the effect of DPT vaccination on diphtheria mortality in this country. [2,3]


  2. Berger S. Infectious Diseases of Thailand, 2019. 506 pages , 169 graphs , 2,339 references. Gideon e-books,
  3. Gideon e-Gideon multi-graph tool,

Note featured on ProMED

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,

Measles Vaccine Effectiveness – Supportive Data

Where data are available, reported rates of measles are inversely related to vaccination coverage.  This observation is true for virtually every country … from Algeria to Zambia  – and are most evident as percentage vaccine coverage exceeds 80 percent.  The following charts are based on WHO statistics for measles incidence and estimates (rather than individual reports) of true vaccine coverage.  Note in the following charts, that when groups of countries are compared, the disease rates themselves are often numerically lower for countries which have attained highest vaccination coverage [1,2]  For  example,  in the third chart, the relatively low vaccine coverage for Africa is reflected in a relatively high disease rate for that region.  The two lower charts depict a decrease in fatal measles cases which have paralleled increasing vaccine coverage.



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

Note features in ProMED





Streptococcus suis Infection in Thailand

Currently, Streptococcus suis infection is more commonly reported in Thailand than a number of more familiar zoonoses acquired from pigs – Trichinosis, Hepatitis E, Brucellosis and Japanese encephalitis. [1,2]   See graph below


  1. Berger S. Infectious Diseases of Thailand, 2019. 506 pages , 169 graphs , 2,339 references.  Gideon e-books,
  2. Gideon e-Gideon multi-graph tool,

Kunjin Virus Infection

The following background information on Kunjin virus infection is abstracted from Gideon and the Gideon e-book series [1]   Primary references are available on request.

Kunjin virus (KUN), a subtype of West Nile virus, was first isolated in Australia in 1960, from mosquitoes (Culex annulirostris).  The virus is named for an Aboriginal clan living on the Mitchell River in Kowanyama, northern Queensland

Most cases of human infection are reported in Australia, with sporadic reports from Nepal. Serosurveys suggest the presence of human infection in Malaysia, Indonesia and Papua New Guinea.

In Australia, Kunjin virus infection is more widely distributed than another flavivirus disease, Murray Valley Encephalitis.  The yearly incidence varies from 0-to-9 cases per year (see Graph).  KUN is reported in most of tropical Australia, eastern Queensland, and occasionally southeastern Australia. The disease appears to have been responsible for some reports of “Murray Valley encephalitis” in 1974, and was implicated in an additional sporadic case in northern Victoria in 1984.  A presumptive case of KUN was reported in Pilbara, Western Australia in 1997.  In 2000, the disease reappeared in Central Australia, where it had last been documented in 1974.  Thirteen cases were reported in Northern Territory during 1992 to 2010, and an outbreak of Kunjin virus encephalitis was reported among horses in New South Wales in 2011.

In 2011, 3.1% of blood donors in Mildura, Victoria were found to be seropositive toward KUN.  The following year, seropositivity was documented in 0.6% to 0.7% of humans and 12.7% of animals in eastern New South Wales.

The principal mosquito vectors for Kunjin virus are Culex annulirostris, Cu. pseudovishnui and Cu. squamosis.  Aedes albopictus has been identified as a potential vector for Kunjin virus in Australia. The virus has also been identified in mosquitoes from Malaysia. Reservoirs include marine birds, pigs and horses.

Kunjin virus infection is often asymptomatic. Overt infection is clinically similar to Ross River disease – arthralgia, fever and rash.


Berger S. Infectious Diseases of Australia, 2019.  551 pages , 165 graphs , 3,407 references. Gideon e-books,

43 cases were reported during 2001 to 2018, New South Wales 3, Northern Territory 5, Queensland 21, Victoria 6 and Western Australia 8.

Individual years:

  1. 1996 – Two cases in Queensland.
  2. 1997 – Two cases in Western Australia and two in Northern Territory.
  3. 2000 – Three in Western Australia and one in Northern Territory).
  4. 2001 – New South Wales, Northern Territory [2 cases] and Western Australia.
  5. 2003 – All cases reported from Queensland
  6. 2004 – 5 in Queensland and 1 in Victoria.
  7. 2005 – 1 in Queensland
  8. 2006 – 2 in Western Australia and 1 in Queensland
  9. 2017 – 1 in Victoria and 5 in Western Australia

Tick-Borne Diseases of Norway

Tick-borne encephalitis (TBE) is one of eight zoonoses carried by ticks in Norway (the others are Anaplasmosis, Babesiosis, Louping ill, Lyme borreliosis, Relapsing fever, Rickettsial spotted fever and Tularemia).  As displayed in the following graphs, rates of human TBE are considerably lower than those of other tick-borne diseases in Norway, and below TBE rates reported by neighboring countries. [1-3]




  1. Berger S. Infectious Diseases of Norway, 2019. 387 pages , 138 graphs , 858 references. Gideon e-books,
  2. Berger S. Tick-borne Encephalitis: Global Status, 2019. 89 pages , 49 graphs , 787 references
  3. Gideon e-Gideon multi-graph tool,

Note featured on ProMED


African Trypanosomiasis: Crossing Borders

141 individual importations (193 patients) of African trypanosomiasis are listed by Gideon  Ten of these patients acquired the disease in Zambia, and 27 were treated in South Africa.

As of February, 2019 the Gideon web application and e-book series [1,2] list 2,718 individual cross-border events, arranged in 134 charts – by disease and country.  Charts also include importation of infected animals (ie, rabid dogs) and contaminated foods and other vehicles which resulted in outbreaks.  Charts in the web application are interactive, and allow the user to sort data according to country, year, number of cases, etc.  In the following screen shots, I have sorted the African trypanosomiasis chart to display cases originating in Zambia (upper box) and cases imported into South Africa (lower box)


  1. Berger S. GIDEON Guide to Cross Border Infections, 2019. 256 pages , 134 tables , 4,543 references. Gideon e-books,
  2. Berger S. African Trypanosomiasis: Global Status, 2019. 84 pages , 40 graphs , 906 references. Gideon e-books,


Venereal Diseases in Australia, the U.K. and the U.S.

As noted in a recent ProMED post, the incidence of gonorrhea, syphilis and genital chlamydial infection are increasing in the United States, United Kingdom and Australia.   I’ve compared recent trends for these diseases in the following graphs, based on data from Gideon [1]  Note that highest rates for all three conditions are consistently reported by the United States.



  1. Gideon e-Gideon multi-graph tool,

Note features on ProMED

Tularemia in Liechtenstein

A recent post in ProMED reported that a hare infected with tularemia had been identified in Liechtenstein.  Although Liechtenstein  reported no cases of human tularemia during January 1, 2003 to November 6, 2018, the neighboring territory of Switzerland has experienced a remarkable increase in disease incidence.  In fact, current rates of human infection in Switzerland are reminiscent of those reported in the United States during the 1930’s. [1-3]


  1. Berger S. Tularemia: Global Status, 2018. 74 pages , 45 graphs , 688 references. Gideon e-books,
  2. Berger S. Infectious Diseases of Liechtenstein. 236 pages , 24 graphs , 10 references. Gideon e-books,
  3. Gideon e-Gideon multi-graph tool,


Rabies in Costa Rica

Recently, a biologist in Costa Rica acquired rabies while working in a cave.  For over five decades, Costa Rica has reported the lowest rates of rabies in Central America (El Salvador reports the highest rates), both in terms of cases and cases per 100,000 population. [1,2]   Costa Rica also reports the lowest incidence of animal rabies for the region.

In the above graph, data for Costa Rica appear as a row of red dots at the lower margin (arrow).


  1. Berger S. Rabies: Global Status, 2018. 475 pages , 557 graphs , 2,570 references
  2. Berger S. Infectious Diseases of Costa Rica, 2018. 334 pages , 120 graphs , 373 references
  3. Gideon e-Gideon multi-graph tool,

Note featured on ProMED