Toxoplasmosis epidemiology and demographics

Toxoplasmosis Microchapters
Home
Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Toxoplasmosis from other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Chest X Ray
CT
MRI
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Therapy
Future or Investigational Therapies
Case Studies
Case #1
Toxoplasmosis epidemiology and demographics On the Web
Most recent articles
Most cited articles
Review articles
CME Programs
Powerpoint slides
Images
American Roentgen Ray Society Images of Toxoplasmosis epidemiology and demographics All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Toxoplasmosis epidemiology and demographics
CDC on Toxoplasmosis epidemiology and demographics
Toxoplasmosis epidemiology and demographics in the news
Blogs on Toxoplasmosis epidemiology and demographics
Directions to Hospitals Treating Toxoplasmosis
Risk calculators and risk factors for Toxoplasmosis epidemiology and demographics

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2] ; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [3]

Overview

Serologic prevalence data indicate that toxoplasmosis is one of the most common human infections throughout the world. Infection is more common in warm climates and at lower altitudes than in cold climates and mountainous regions. High prevalence of infection in France has been related to a preference for eating raw or undercooked meat, while high prevalence in Central America has been related to the frequency of stray cats in a climate favoring survival ofoocysts. The overall seroprevalence in the United States as determined with specimens collected by the third National Health and Nutritional Assessment Survey (NHANES III) between 1988 and 1994 was found to be 22.5%, with seroprevalence among women of childbearing age (15 to 44 years) of 15%.

Epidemiology

Prevalence

• It is estimated that 25 to 30% of the world's population is infected with toxoplasma.
• In United States 89% of women in the childbearing age are susceptible to have an acute infection and at risk for transmitting the parasite to the baby if the primary infection occurs during the gestational period.
• In United States the age adjusted seroprevalence rate is 22.5%. There is significant variation in the distribution with highest prevalence reported in the North-eastern states and lowest in the western states.
• In countries such as North America, Northern Europe and in Sahelian countries of Africa low seroprevalences of 10% to 30% are observed. In countries of Central and Southern Europe, tropical African countries and Latin America the seroprevalence is around 30 to 50%. This shows the variation within the countries and as well as between the countries.

Incidence

• In United States, toxoplasmosis affects 1.1 million people every year.
• Congenital toxoplasmosis affects 500 to 4000 new borns every year.

Demographics

Age

• The U.S. NHANES (2004-2005) national probability sample found that 33.1% of U.S. persons above 12 years of age had Toxoplasma-specific IgG antibodies, indicating that they had been infected with the organism.
• This prevalence has significantly increased from the 1999-2000 data.

Race

• In NHANES 1999–2000, the T. gondii antibody prevalence was higher among non-Hispanic black persons than non-Hispanic white persons.
• This finding may reflect immigration patterns from countries with higher rates of T. gondii infection or soil exposure and culinary practices among these different populations.
• The seroprevalence among persons born outside the United States tended to be higher in NHANES 1999–2000 than in NHANES III, and the percentage of persons born outside the United States tended to be higher in NHANES 1999–2000 than NHANES III, but these findings were not statistically significant.
• Clearly, in both NHANES III and NHANES 1999–2000 the seroprevalence is higher among persons not born in the United States than in U.S.-born persons.
• The NHANES 1999–2000 sample population is not large enough to stratify racial/ethnic groups by foreign-birth status and obtain accurate estimates; however, in a multivariate analysis reported previously that used NHANES III data, being born outside the United States was a significant risk factor for T. gondii seropositivity.
• However, race/ethnicity did not increase risk (using white non-Hispanic persons as the reference group).

Geographic distrubution

United States

• There was found to be an overall T. gondii IgG antibody prevalence of 15.8% among persons 12–49 years of age in 1999–2000, indicating that approximately 1 in 6 persons in this age group was infected with T. gondii.
• No significant changes in T. gondii seroprevalence occurred between 1988–1994 and 1999–2000 for the U.S. population as a whole or for any of the subgroups we examined.
• It was speculated that changes in meat production with lower levels of T. gondiiin meat might result in a reduction in the prevalence of T. gondii infection in the population.
• Perhaps the time was not sufficient for changes in meat production and consumption habits to have had an impact, or perhaps the expected declines in T. gondii infection occurred before NHANES III.
• The prevalence of T. gondii infection declined in U.S. military recruits, when 1965 data were compared with 1989 data and in countries in Europe, such as France and Belgium, during similar periods.
• Predicting future trends in T. gondii prevalence in the United States is difficult because we do not have a national estimate of what proportion of T. gondii infections are attributable to undercooked meat exposure or to cat feces, soil, or water exposure.
• A large European case-control study that examined these factors showed that undercooked meat accounted for the largest portion of risk for T. gondii infection (30%–63%, depending on location).
• However, until researchers examine the risk factors for T. gondii infection in a case-control study throughout the United States, the most important U.S. risk factors and how to best focus preventive education messages will not be determined.
• NHANES gives representative estimates of prevalence for the U.S. population but is not designed to evaluate local T. gondii prevalence levels.
• Studies have indicated that T. gondii prevalence varies greatly in the United States; this local variation is most likely related to culinary practices, the ability of oocysts to survive in different climates, and the levels of immigration from areas of the world in which T. gondii infection is highly endemic.
• Nevertheless, NHANES produces useful surveillance data for tracking T. gondii prevalence over time in the United States. We will continue to monitor trends in this nationally representative survey.

Other Regions of the World

• It is estimated that between 30% and 65% of all people worldwide are infected with Toxoplasmosis.
• However, there is large variation countries: in France, for example, around 88% of the population are carriers, probably due to a high consumption of raw and lightly cooked meat.
• Germany, the Netherlands and Brazil also have high prevalences of around 80%, over 80% and 67% respecti ely. In Britain, about 22% are carriers, and South Korea's rate is only 4.3%.

References

Template:WikiDoc Sources