Archive for the ‘Epidemiology’ Category

Dirofilariasis in Russia

Tuesday, November 22nd, 2011

The following background information on dirofilariasis is abstracted from Gideon www.GideonOnline.com.

Subcutaneous dirofilariasis is reported in Astrakhan, Volgograd, Nijegorodskiy, Saratov, Rostov, Chelyabinsk and several other oblasts.
- 564 cases were reported between 1915 and 2008 , of which 68.5% were in the endemic area of Russia
- 114 cases of subcutaneous infection by Dirofilaria repens were reported for the former Soviet Union during 1915 to 1996.
- All infections were acquired below 53 degrees N. latitude, and the majority were diagnosed during January to June.

11 cases were reported in the Moscow region during 2000 to 2002, many involving the male genitalia.
- 129 cases of human subcutaneous dirofilariasis and 2 of pulmonary dirofilariasis were identified in the Rostov region during 2000 to 2009.
- 14 cases of human subcutaneous dirofilariasis due to Dirofilaria repens were confirmed in Rostov-on-Don during February 2003 to July 2004.
- 2 cases were reported in the Kirov region in 2008
- 8 cases of Dirofilaria repens infection were reported in the Primorye Territory over a three-year period (2011 publication)

In recent years, Dirofilaria immitis has been replacing Dirofilaria repens as a dog pathogen in the Rostov region.

Prevalence surveys:
20.25% of dogs in the Rostov region – of these, 44.7% D. repens, 30.3% D. immitis and 25.0% coinfection by both species (2011 publication)

Seroprevalence surveys:
10.4% of blood donors and 19% of policemen in the Rostov region (2011 publication)

Tuberculosis: Reported Disease Trends vs. BCG Vaccine Uptake

Monday, November 21st, 2011

A recent posting in ProMED noted that rates of tuberculosis in North Korea have been increasing at an alarming rate in recent years, in spite of a parallel improvement in the uptake of BCG vaccine in that country. Indeed, one of the oldest controversies in medicine concerns the effectiveness of BCG vaccination to prevent tuberculosis. As of 2011, over 85% of countries continue to routinely vaccinate infants with BCG vaccine.

The following analysis was undertaken to collate concurrent trends in tuberculosis rates and BCG vaccine uptake among countries which employ the vaccine. Data for tuberculosis incidence were obtained from the Gideon database (www.GideonOnline.com) which is largely based on reporting from individual Health Ministry reports and publications of the World Health Organization. Disease rates per 100,000 population are automatically generated by Gideon, and all charts summarized in a related e-book. [1] Country-specific estimates of BCG coverage were obtained from a WHO website: http://apps.who.int/immunization_monitoring/en/globalsummary/timeseries/tscoveragebcg.htm , and supplemented by individual reporting data at http://www.who.int/countries/en/ .

Individual charts were generated which plot tuberculosis rates and estimates of vaccine uptake. [2] Charts were then collated into three categories:

A) Tuberculosis rates appear to diminish in parallel with high (>=85%) and / or increasing vaccine uptake (examples in graph A)

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B) tuberculosis rates appear to increase in parallel with high and / or increasing vaccine uptake (examples in graph B)

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C) no consistent similarity is apparent between trends in tuberculosis rates and vaccine uptake (examples in graph C).

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The latter graph also includes examples of countries (Latvia, Peru and India) in which vaccine update was initially associated with increasing disease rates, and subsequently decreasing rates; and others (Sri Lanka) in which these effects were reversed.

No attempt was made to further examine these data using tests of statistical significance, trend analysis, etc. In the following table, assignment of individual countries is based simply on the existence of overt visible trends between disease rates and vaccine uptake:


Data presented in the table suggest that only 62 countries (36%) which employ BCG vaccination have demonstrated decreasing tuberculosis rates in parallel with increased vaccine uptake; while, 49 countries (28%) have actually experienced increasing disease rates despite adequate vaccine usage. There is no apparent relationship between vaccination and disease rates in the remaining 63 countries (36%) . Countries in which a paradoxical increase in tuberculosis has paralleled expanded vaccine uptake are concentrated in Africa, Asia and the Near East; while countries in which increasing vaccine uptake is paralleled by decreased incidence are concentrated in North Africa, the Middle East, Western Europe, Oceania and the Americas region. These trends are depicted in the following map:


The above analysis is not intended to imply a causal relationship between tuberculosis incidence and vaccine uptake. In fact, any impact of BCG vaccination on disease incidence might only become apparent after several years, given the long “incubation period” associated with reactivation tuberculosis. Additional factors which might impact on the incidence of tuberculosis in many of these countries include AIDS, malnutrition, crowding, civil conflict, drug resistance, nature of laboratory facilities, and systems for case-finding, patient isolation and follow-up.

References:
1. Berger SA. Tuberculosis: Global Status, 2011. 568 pages, 894 graphs, 1142 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/tuberculosis-global-status/
2. Gideon graph tool tutorial at http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps

Posted by ProMED

Venereal Diseaes in the United States

Wednesday, November 16th, 2011

The following graphs summarize six decades of venereal diseases data for the United States. As described in a recent ProMED report, the incidence of syphilis has been rising since 1999. 1,2 Note that reports of chlamydial infection have increased arithmetically since the disease became reportable in 1994.


(Graph tool tutorial at
http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of the United States, 2011. 1030 pages, 464 graphs, 8237 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-the-united-states/
2. Berger SA. Syphilis: Global Status, 2011. 231 pages, 336 graphs, 861 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/syphilis-global-status/

Featured on ProMED

Tuberculosis in North Korea

Sunday, November 13th, 2011

[comment on Tuberculosis, drug resistance - North Korea ]

Rates of tuberculosis in North Korea continue to increase at an alarming rates, and are currently similar to those reported in South Korea during the 1970′s (see graph below). Strangely, these increases have paralleled WHO estimates of BCG vaccine uptake in this country (yellow line in graph). 1,2

(Graph tool tutorial at http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of North Korea, 2011. 315 pp, 25 graphs, 840 references. Gideon e-book series, http://www.gideononline.com/ebooks/country/infectious-diseases-of-north-korea/
2. Berger SA. Tuberculosis: Global Status, 2011. 568 pages, 894 graphs, 1142 references. Gideon e-book series, http://www.gideononline.com/ebooks/disease/tuberculosis-global-status/

Featured on ProMED

Hepatitis B and Liver Cancer: California

Saturday, October 22nd, 2011

[comment on Hepatitis B - United States of America (California) Liver Cancer]

Changes in vaccination policy may not solve California’s “liver cancer epidemic.” In the United States as a whole, rates of Hepatitis B were had already declined significantly before the demonstration of effective vaccine uptake [1,2] See graph :

Vaccination of infected Asian immigrants cannot alter disease progression or public health risk among Asian immigrants who were already infected before arriving to California. The focus must be on testing and counseling of pregnant carriers and high-risk contact groups in this community. In any case, possible effects of increased vaccination on rates of liver cancer might not be apparent for several years, given the natural lag period from infection to tumor.

(See the Graph tool tutorial at www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of the United States, 2011 publication. 1030 pp, 464 graphs, 8237 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-the-united-states/
2. Berger SA. Hepatitis B: Global Status, 2011. 327 pp, 405 graphs, 1517 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/hepatitis-b-global-status/

Note cited by ProMED

Plague in Madagascar

Friday, October 14th, 2011

The following background data on plague in Madagascar were abstracted from Gideon www.GideonOnline.com and the Gideon e-book series. [1,2] (Primary references are available on request)

Time and Place:
– Plague was first described in Madagascar in 1898, with cases in the harbor of Tamatave (Toamasina).
– The first epidemic occurred in Majunga in 1902 (142 fatal cases during May to July of that year).
– Subsequent outbreaks were reported in Majunja in 1907 (49 fatal cases), 1924 and 1928.
– The disease reached the central highlands in 1921, and remains endemic to this area at elevations above 800 m.
– Outbreaks of pneumonic plague were reported during 1921 to 1935; and in 1957 (northeast region).
– Plague was first reported in port areas of Madagascar in 1898; with later spread to the high plateau in 1921.
– During 1989 to 1992, 93% of cases were reported from “the plague triangle” located in the Central Highlands and delimited by Ambatondrazaka, Miarinarivo and Fianarantsoa.

Biology and transmission:
– Reservoirs implicated in transmission include the shrews (Suncus murinus) and rats (Rattus rattus).
– Infection has also been identified in hedgehogs (Tenrec ecaudatus).
– Possible flea vectors include Paractenopsyllus pauliani, Synopsyllus fonquerniei and Xenopsylla cheopis.

Incidence:
Two major waves of plague have been reported – with peak incidence in 1932 (3,656 cases) and 1997 (2,863 cases). See graph:

– 10,471 cases were reported during 1935 to 1949 ; 9,227 (448 fatal) during 1957 to 1986; 5,896 (493 fatal) during 1980 to 1997; 11,673 (950 fatal) during 1987 to 2001.
– Of 5,927 suspected cases reported during 1989 to 1995, 1,337 were bacteriologically-confirmed, with a case-fatality rate of 19%.
– 1,702 suspected cases (515 confirmed, 47 fatal) were reported in Mahajanga during 1995 to 1998.
– 91.3% of these cases were characterized as bubonic (67.8% of these involving the inguinal region).

Africa accounts for most of the world’s plague deaths. >=50% of these deaths are reported by Madagascar. See graph:

Seroprevalence surveys:
<1.5% to 15.5% in Majanga City (1997 publication)
0.61% of persons in Mahajanga (anti-F1 antibody, 1999)
3.2% of market vendors in Antananarivo (anti-F1 antibody, 1999)

Notable outbreaks:
1982 (publication year) – An outbreak (9 cases) was reported in Tananarive.
1991 – An outbreak was reported in Majunga.
1995 – An outbreak (108 confirmed and presumed cases) was reported in Mahajanga city.
1997 – An outbreak (2,863 cases, 176 fatal) was reported.
1998 – An outbreak was reported in a hamlet in the Ikongo district.
2008 – An outbreak (7 deaths) of pneumonic plague was reported in Toamasina.
2010 – An outbreak (31 cases, 1 fatal) was reported in La Libertad.
2011 – Outbreaks (200 cases, 60 fatal) were reported, including Antananarivo (3 fatal cases) and Antsiranana (16 fatal cases).

(outline of Gideon Graph module – see http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of Madagascar, 2011. 49 pp, 47 graphs, 1,029 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-madagascar/
2. Berger SA. Plague: Global Status, 2011. 95 pages, 101 graphs, 485 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/plague-global-status/

Bartonellosis in Peru

Tuesday, October 11th, 2011

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

Seasonality / Distribution:
- South American bartonellosis is primarily found in the Western Andes river valleys at elevations of 500 to 3000 meters – Ancash, La Libertad, Cajamarca and Amazonas.
- Cases are reported at elevations as high as 3,375 meters (town of Huasta).
- During 2004 to 2007, 36.1% of cases were reported from Cajamarca, 30.3% Ancash, 17.3% La Libertad and 8.0% Amazonas

Indidence – see graph:

Chronology:
1871 – 7,000 workers died of bartonellosis during the building of a railway line from Lima to Oroya. (thus the term, “Oroya fever.”)
1906 – An outbreak (200 fatal cases) was reported among tunnel workers.
1959 – An outbreak (200 fatal cases) was reported in Anco.
2003 – 31 fatal cases were reported. 3,431 cases were reported in Ancash and 1,220 in La Libertad.
2004 – 4,087 cases were reported in Jaen and 3,979 in Ancash.
2007 – 1,857 cases (12 fatal) of acute infection 584 of chronic infection were reported.
2011 – A fatal case was reported in the Lambayeque region.
1987 – An outbreak (554 cases, 14 fatal) was reported in Shumpillan Village (Pomabamba Province).
1998 – Outbreaks were reported in new focus in the Urubama region (20 cases), and in Cuzco Department.
2006 – An outbreak (10 cases) was reported in a new focus in Arahuan District, Lima Province.

Vectors:
- The local sand-fly vector is Lutzomyia verrucarum.
- L. maranonensis and L. rubusta have also been implicated.

Reference:
1. Berger SA. Infectious Diseases of Peru, 2011. 401 pp, 92 graphs, 1,282 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-peru/

Outbreaks of Toxoplasmosis

Thursday, October 6th, 2011

Despite a widespread prevalence of toxoplasmosis among humans and other vertebrates, overt outbreaks are rarely reported. The following chronology is abstracted from Gideon (www.GideonOnline.com) and the Gideon e-book series. [1] (Primary references available on request)

Outbreaks among humans:
1967 (publication year) – Brazil. An outbreak at a Paulist seminary in Braganza, Sao Paulo State.
1969 (publication year) – Brazil. An outbreak of toxoplasmosis at a university in Sao-Jose-dos Campos, Sao Paulo.
1977 – United States. An outbreak (37 cases) in Georgia among patrons of a riding stable.
1978 – United States. An outbreak (10 cases) among members of a family in California, associated with consumption of raw goat’s milk.
1979 – Italy. An outbreak (5 cases) among members of a family.
1980 (publication year) – United States. An outbreak (10 cases) in an extended family, related to cat contact.
1981 (publication year) – United States. An outbreak in Georgia.
1982 (publication year) – Brazil. An outbreak in a rural area.
1984 (publication year) – United States. An outbreak (9 cases) among family members on an Illinois farm.
1984 (publication year) – Australia. An outbreak (5 cases) among members of a Lebanese family in Australia was ascribed to contaminated Kibbi (a traditional meat dish)
1990 (publication year) – Canada. 4 cases among pregnant women in Quebec, associated with consumption of raw meat.
1993 – Brazil. An outbreak (20 cases) in Parana was ascribed to ingestion of contaminated mutton.
1995 – Canada. An outbreak (2,895 to 7,118) cases in the Greater Victoria area of British Columbia. This was the largest recorded outbreak of toxoplasmosis from water
1997 (publication year) – Republic of Korea. Two outbreaks (8 cases) associated with consumption of uncooked pork.
2001 – Brazil. A water-borne outbreak (176 cases) in Parana
2002 – Brazil. A water-borne outbreak (426 cases) in Parana
2002 – Turkey. An outbreak (171 cases) at a boarding school in Izmir.
2003 to 2004 – French Guiana. An outbreak (11 cases, 3 fatal) in Patam, among immunocompetent patients.
2010 (publication year) – India. An outbreak (248 cases) of Toxoplasma retinitis in Tamil Nadu was ascribed to ingestion of contaminated water

Veterinary outbreaks:
1953 (publication year) – Norway. An outbreak among chickens
1964 (publication year) – Canada. An outbreak (44 cases) chinchillas (Chinchilla lanigera) in Ontario.
1977 (publication year) – Sweden. An outbreak of among pigs.
1977 – United States. An outbreak (4 cases) among wallaroos (Macropus robustus) in a California zoo.
1986 (publication year) – United States. An outbreak among captive kangaroos, wallabies, and potaroos.
1986 (publication year) – Italy. An outbreak on an bird-farm in Vicenza involved small passerine birds (Serinus canaria, Carduelis chloris, Carduelis carduelis, Carduelis spinus, Carduelis cannabina and Pyrrhula pyrrhula).
1992 (publication year) – United States. An outbreak among wallabies on an exotic animal farm.
1992 (publication year) – United Kingdom. An outbreak of toxoplasmosis among captive squirrel monkeys (Saimiri sciureus)
1996 – Czezh Republic. An outbreak among Angora goats.
1999 – United States. An outbreak among Wisconsin mink (Mustela vison).
2004 – China. An outbreak among swine in Ganzu Province.
2008 (publication year) – Israel. An outbreak (19 cases) among captive squirrel monkeys (Saimiri sciureus) was ascribed to contaminated feed.
2008 (publication year) – South Africa. An outbreak (8 cases) among Nicobar pigeons (Caloenas nicobaria) in an aviary collection.
2009 (publication year) – Italy. An outbreak among ovines on a farm.
2009 (publication year) – Republic of Korea. An outbreak of porcine abortion due to toxoplasmosis was reported in Jeju Island.

Reference:
1. Berger SA. Toxoplasmosis: Global Status, 2011. 92 pp, 74 graphs, 950 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/toxoplasmosis-global-status/

Botulism in the United States

Thursday, October 6th, 2011

Notwitstanding a recent outbreak in Utah, infant botulism has accounted for an growing percentage of total cases in recent years. [1,2] In the following graph, I’ve summarized trends for botulism in the United States. Note that total case numbers have been increasing since 1995, despite a decrease in the incidence of food-borne botulism.

(See the Graph tool tutorial at www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps )

References:
1. Berger SA. Infectious Diseases of the United States, 2011. 1030 pp, 464 graphs, 8237 references. Gideon e-books, www.gideononline.com/ebooks/country/infectious-diseases-of-the-united-states/
2. Berger SA. Botulism: Global Status, 2011. 80 pages, 86 graphs, 510 references. Gideon e-books, http://www.gideononline.com/ebooks/disease/botulism-global-status/

Intestinal Protozoa in the United States

Saturday, October 1st, 2011

Notwithstanding a recent outbreak in Georgia, Cyclospora is the least common intestinal protozoan reported in the United States. [1] In the following chart, I have summarized the incidence of cyclosporiasis, giardiasis, amebiasis and cryptosporidiosis. As indicated at the black arrow, ongoing trends for amebiasis (no longer reported as of 1994 = 2,983 cases) were “continued” by reports of cryptosporidiosis (2,972 cases in 1995).

(outline of Gideon Graph module – see http://www.GIDEONonline.com/wp/wp-content/uploads/Gideon-Graphs.pps)

Reference:
1. Berger SA. Infectious Diseases of the United States, 2011. 1030 pp, 464 graphs, 8237 references. Gideon e-books, www.gideononline.com/ebooks/country/infectious-diseases-of-the-united-states/

Note published in ProMED