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Archive for the ‘Epidemiology’ Category

Varicella vs. Monkeypox

Outbreaks of varicella and monkeypox in Africa are occasionally mistaken for “smallpox”   The following table was generated by an interactive tool in Gideon ( which allows users to generate custom charts that contrast clinical features, drug spectra or microbial phenotypes.




Rabies and Leishmaniasis in Algeria

Although high rates of rabies and leishmaniasis in Boghni district, Algeria could reflect a common dog reservoir ( , reporting statistics on a national level do not suggest that the diseases are related.  See chart:

Note featured in ProMED


Enterohemorrhagic E. coli in Scandinavia

Although rates of enterohemorrhagic E. coli (EHEC) infection have been increasing in Scandinavia since 2000, trends for E. coli O157 are less clear.  The following charts generated by Gideon ( display relevant data for Denmark, Finland, Norway and Sweden.



Human Metapneumovirus in India

As of October 2017, the Gideon database ( chronicles 57,331 prevalence- and seroprevalence surveys.  Data relevant to Human metapneumovirus in India follow below.

60% of New Delhi children below age 5 years were found to be seropositive toward Human metapneumovirus, increasing to >80% by age 55 years (2011 publication)


Prevalence surveys:

2004 – 2005 / Delhi / 12% of acute respiratory infections in children below age 5 years

2005 – 2007 / Delhi / 3% of children with acute respiratory infection

2005 – 2007 / Delhi / 3.6% of children (<5 years) with acute lower respiratory tract infection treated at a hospital

2012 – 2014 / Odisha / 2.11% of children with acute respiratory tract infection

2014* /  Lucknow / 1.1% of acute lower respiratory tract infections among hospitalized children

2014* / Assam / 7.2% of outpatient children with respiratory illness

2016* / Rajasthan / 25.7% of hospitalized children ages <=5 years with severe acute respiratory

2006 – 2009 / Kolkata /     5.11% of nasal and/or throat swabs from outpatients with acute respiratory tract infection

2010 – 2011 / Eastern India / 3% of patients with acute respiratory tract infection

2011 – 2013 / Southern India / 5% of patients with acute respiratory infection

     * indicates publication year (not necessarily year of survey)


Note featured on ProMED

Tick-borne Encephalitis in Switzerland

Rates (per 100,000) of tick-borne encephalitis in Switzerland have increased somewhat since the year 2000, and are currently higher than those reported by surrounding countries.  The following image was created by a tool in Gideon ( that converts incidence data into population rates and combines user-selected graphs into a single chart.

Note featured in ProMED

Bacterial Diarrhea in Norway

As noted in a recent ProMED posting, salmonellosis is the second most common cause of bacterial diarrhea in Norway.  The following charts were generated by a multi-graph tool in Gideon  As in many countries, Campylobacter is the leading pathogen in this group.  Note that for the past two decades, rates of salmonellosis in Scandinavia have been somewhat higher than those in the United States.  Rates of shigellosis have been slightly higher in the United States than in Norway


Salmonellosis in Norway and the United States

A recent ProMED post suggested that outbreaks of salmonellosis in the Scandinavian countries are less common than in the USA.  Putting aside confounding factors related to differing surveillance systems, case definitions, etc the definition of “common” is problematic.  Thus the following chart generated by Gideon ( demonstrates that disease incidence is in fact much higher in the United States; but, when adjusted for population, Norway has experienced higher salmonellosis rates (per 100,000 population) through much of the past two decades.

Similarly, the highest number of food-related salmonellosis outbreaks reported in Norway in recent years was only eleven (in 2008), vs. 161 outbreaks in the United States (in 2013).  When adjusted for population size, these figures translate into 0.24 outbreaks per 100,000 population in Norway,  vs. only 0.051 per 100,000 in the United States.

Hepatitis A and Israel

The potential benefit for Hepatitis A (HepA) vaccination in Jordan is illustrated by the following chart.  In 1999, Israel became the world’s first country to institute routine HepA immunization (blue arrow), and and has since largely eradicated the disease. [1]



  1. Chart generated by a Gideon multi-graph tool, see

Note featured on ProMED


The following background data on Thelaziasis are abstracted from Gideon  Primary references are available from the author.

Thelaziasis (“oriental eye worm”) in humans was first reported in China in 1917, and autochthonous cases were initially limited to Asia.  Over 1,000 cases of human infection were estimated for Asia during a 20-year period (2016 publication)  Cases have since been reported in Africa, Asia, Europe and North America.  The condition is most common during summer and fall, and involves proximity to dogs.  61% of patients are either elderly adults, or children ages three to six years.

Two of the 16 known species of Thelazia have been reported in humans: T. callipaeda and T. californiensis.  Thelazia callipaeda is a parasite of canids, felids and rodents.  Cases of human and animal infection by this species have been reported in several countries, including Bangladesh, Belgium, China, Croatia, France, Germany, India, Italy, Japan, Portugal, Republic of Korea, Serbia, Spain, Taiwan and Thailand. Thelazia californiensis is a parasite of canids, felids and domestic and wild ruminants.  The species is found in North America (California and the Rocky Mountain region).

These parasites are transmitted by non-biting flies which acquire first stage larvae while feeding on ocular secretions, tears and conjunctivae of mammals. The fly vectors of Thelazia callipaeda are Portica variegataAmiota okadai and Amiota variegata.

The fly vectors of Thelazia californiensis are Musca autumnalisFannia canalicularis and Fannia benjamini.

The signs and symptoms of human thelaziasis are related to the presence of a worm in the conjunctival sac, and consist of pain, lacrimation and a foreign body sensation.

Animal infection involves the area under the eyelids, nictitating membrane, nasolacrymal ducts, conjunctival sac and lacrimal glands. The thread-like adult worms reach a length of 12 to 20 mm and are identified in the conjunctival sac. Adult worms live for up to one year.

Hookworm in the United States

The following background data on hookworm in the United States are abstracted from Gideon  Primary references are available on request.

Hookworm was formerly common in the South and Southeast, with highest rates among children.  7,391 cases of ancylostomiasis were officially notified through optional reporting during 1967 to 1969, including 4,831 (65.4%) from Georgia.  In 1987, 68.7% of positive state laboratory reports were submitted from California, Wisconsin, Rhode Island, Colorado and Washington.

Prevalence surveys:

Year(s) / Region / Details

1909-1914 / South / 40% of the general population

1942 / Appalachia / 14.6% of college students

1955 / Tennessee / 19.6% of rural school children

1955 / Kentucky / 0.5% of the general population in eastern region

1965 / Kentucky / 3.6% of native-born children in eastern region

1969 / North Carolina / 3.0% of Cherokee Indian school children

1970 / Kentucky / 14.8% of rural school children

1972 / South Carolina / 1.8% of school children in coastal region

1972 / Georgia / 4.6% of rural white children

1972 / Georgia / 13.6% of rural white and African-American population

1972 / Louisiana / 0.4% of the low-income population

1974 / Louisiana / 0.1% of kindergarten children in New Orleans

1975 / Louisiana / 0.1% of young children in southwest region

1975 / Illinois / 6.6% of Latino residents of Chicago

1981 / California / 2% (Mexican) and 25% (Indochinese) of immigrants

1982 / Kentucky / 0.2% of native-born children ages 3 to 7 years

1982 / NS / 20% of Southeast Asian immigrants

1987 / multiple / 1.5% of stool specimens submitted to state laboratories

1993-2007 / Minnesota / 9.2% of African and Southeast Asian immigrants

1995 / Washington / 4.5% of Southeast Asian immigrants in Seattle

1996-2001 / Minnesota / 2% of refuges at first screening visit

2008-2010 / California / 1.1% of recently-arrived refugees

Not unexpectedly, hookworm is also identified among military personnel serving in endemic regions.  For example, in 1975 hookworm was found in 0.9% of American aircrew members serving in Southeast Asia; while in 1983, an overt outbreak (35 cases) was reported among American soldiers following the invasion of Grenada.