Search

Toxoplasma gondii can cause severe neurologic and ocular disease when transmitted congenitally and in immunosuppressed persons. Sera collected in the National Health and Nutrition Examination Survey 2011 through 2014 in 13,507 persons ≥ 6 years old were tested for T. gondii immunoglobulin (Ig) G and IgM antibodies, and in those both IgG and IgM antibody positive, for IgG avidity. Overall, 11.14% (95% confidence limits [CL] 9.88%, 12.51%) were seropositive for T. gondii IgG antibody (age-adjusted seroprevalence 10.42% [95% CL 9.19%, 11.76%]); in women aged 15-44 years, the age-adjusted T. gondii IgG seroprevalence was 7.50% (95% CL 6.00%, 9.25%). In multivariable analysis, risk for IgG seropositivity increased with age and was higher in males; persons living below the poverty level; persons with ≤ a high school education compared with those with > a high school education; and non-Hispanic black, Mexican American, and foreign born non-Hispanic white persons compared with U.S.-born non-Hispanic white persons. Overall, 1.16% (95% CL 0.94%, 1.42%) were T. gondii IgM antibody positive and 0.71%, (95% CL 0.54%, 0.92%) were both IgM and IgG antibody positive. In multivariable analysis, the significant risk factors for being both IgM and IgG positive were older age, crowding, and non-U.S. birth origin compared with U.S.-born persons. Among those positive for both IgM and IgG antibody, almost all had high avidity (all women aged 15-44 years had high avidity). Toxoplasma gondii antibody prevalence remains relatively low in the United States, although it is higher in non-U.S.-born persons, males, and some minority and socioeconomically disadvantaged groups.

An estimated 50 million persons worldwide are infected with cysticerci, the larval forms of the Taenia solium tapeworm. Neurocysticercosis can cause seizures, epilepsy, and hydrocephalus, and fatal cases have been reported in the United States in immigrants and in travelers returning from endemic countries. Pregnant women with symptomatic neurocysticercosis present treatment challenges, whereas those with the adult tapeworm infection (i.e., taeniasis) can put their infants and other family members, as well as obstetrician-gynecologists and their staff, at risk for cysticercosis. A questionnaire developed by the American College of Obstetricians and Gynecologists was sent to a representative sample of 1,000 physicians to assess their awareness of T. solium infection and the potential for it to be encountered in an obstetrics and gynecology setting. In total, 31.4% of respondents correctly answered that taeniasis is caused by eating undercooked pork containing T. solium cysts (95% confidence interval [CI] = 26.6-36.5). While only 14.5% (95% CI = 11.0-18.6) of respondents correctly answered that cysticercosis is acquired by ingesting tapeworm eggs shed in human stools, twice that number (30.3%; 95% CI = 25.5-35.3) correctly answered that a mother with taeniasis can cause cysticercosis in her infant. Practicing in a state in which cysticercosis was reportable at the time of the survey was not significantly associated with answering any of the 12 knowledge questions correctly. Overall, knowledge of T. solium infection among U.S. obstetricians-gynecologists is limited. This may result in missed opportunities to diagnose and treat pregnant women with taeniasis, which may put family members and obstetrics clinical staff at risk for cysticercosis., (© The American Society of Tropical Medicine and Hygiene.)

In 1977, an outbreak of toxoplasmosis occurred among 37 persons associated with exposure to an indoor horse arena. Cat feces containing the organism were most likely stirred up when horses ran on the dirt floor, and were inhaled or ingested by riders and observers. After 25 or more years, we attempted to locate persons from the outbreak and offer them an eye examination. Of the 37 persons in the outbreak, 18 (49%) were located; four had died, and the remaining 14 agreed to an examination. Among the 14 persons examined, three (21%) were found to have lesions typical of toxoplasmic retinochoroiditis. If these three persons were the only ones with ocular disease among the 37 persons in the outbreak, the disease rate would still be high (8%). As a result of exposure to Toxoplasma gondii during this outbreak, a relatively high percentage of persons developed ocular disease., (© The American Society of Tropical Medicine and Hygiene.)

Toxoplasma gondii is a ubiquitous parasite that can cause neurologic and ocular disease. We tested sera from 7,072 people ≥ 6 years of age in the 2009-2010 National Health and Nutrition Examination Survey (NHANES) for immunoglobulin G antibodies and compared these results with two previous NHANES studies. The overall T. gondii antibody seroprevalence among persons ≥ 6 years of age in 2009-2010 was 13.2% (95% confidence limit [CL] 11.8%, 14.5%) and age-adjusted seroprevalence was 12.4% (95% CL 11.1%, 13.7%); age-adjusted seroprevalence among women 15-44 years of age was 9.1% (95% CL 7.2%, 11.1%). In U.S. born persons 12-49 years of age, the age-adjusted T. gondii seroprevalence decreased from 14.1% (95% CL 12.7%, 15.5%) in NHANES III (1988-1994) to 9.0% (95% CL 7.6%, 10.5%) in NHANES 1999-2004 to 6.7% (95% CL 5.3%, 8.2%) in NHANES 2009-2010 (P < 0.001 linear trend). Although T. gondii antibody presence is still relatively common, the prevalence in the United States has continued to decline., (© The American Society of Tropical Medicine and Hygiene.)

Toxoplasma gondii is a leading cause of severe foodborne illness in the United States. Population-based studies have found T. gondii infection to be more prevalent in racial/ethnic minority and socioeconomically disadvantaged groups. Soil contaminated with cat feces, undercooked meat, and congenital transmission are the principal sources of infection. Toxoplasmosis-associated illnesses include congenital neurologic and ocular disease; acquired illness in immunocompetent persons, most notably ocular disease; and encephalitis or disseminated disease in immunosuppressed persons. The association of T. gondii infection with risk for mental illness is intriguing and requires further research. Reduction of T. gondii in meat, improvements in hygiene and food preparation practices, and reduction of environmental contamination can prevent toxoplasmosis, but more research is needed on how to implement these measures. In addition, screening and treatment may help prevent toxoplasmosis or reduce the severity of disease in some settings.

In October of 2008, an outbreak of trichinellosis occurred in northern California that sickened 30 of 38 attendees of an event at which meat from a black bear was served. Morphologic and molecular testing of muscle from the leftover portion of bear meat revealed that the bear was infected with Trichinella murrelli, a sylvatic species of Trichinella found in temperate North America. Clinical records revealed a high attack rate for this outbreak: 78% for persons consuming any bear meat and 100% for persons consuming raw or undercooked bear meat. To our knowledge, this report is the first published report of a human trichinellosis outbreak in the United States attributed to T. murrelli, and it is the second such outbreak reported worldwide.

Chagas disease affects an estimated 300,000 people in the United States, and as many as 300 congenital infections are estimated to occur annually. The level of knowledge about Chagas disease among obstetricians-gynecologists in the United States has not been assessed. The American College of Obstetricians and Gynecologists surveyed a representative sample of 1,000 members about Chagas disease. Among 421 respondents, 68.2% (95% confidence interval [CI] = 63.5-72.6) described their knowledge level about Chagas disease as "very limited." Only 8.8% (95% CI = 6.2-12.0) knew the risk of congenital infection, and 7.4% (95% CI = 5.1-10.4) were aware that both acute and chronic maternal infections can lead to congenital transmission. The majority of respondents (77.9%; 95% CI = 73.5-81.9) reported "never" considering a diagnosis of Chagas disease among their patients from endemic countries. Most of those who did consider the diagnosis did so "rarely." Knowledge of Chagas disease among obstetricians-gynecologists in the United States is limited. Greater awareness may help to detect treatable congenital Chagas cases.

Toxoplasmosis is the most common retinal infection in the United States, and it can severely impact vision. We used data from population-based studies, outbreaks, and the U.S. census to estimate the burden of Toxoplasma gondii infection and ocular toxoplasmosis. We estimate that 1,075,242 persons are infected with T. gondii, 21,505 persons have ocular lesions (both asymptomatic and symptomatic), and 4,839 (range = 2,150-7,527) persons develop symptomatic ocular toxoplasmosis each year in the United States. Toxoplasmosis contributes a significant burden to eye disease in the United States.

To estimate the prevalence of Toxocara spp. infection in a representative sample of the United States population >or= 6 years of age, sera from participants in the Third National Health and Nutrition Examination Survey (1988-1994) were tested for antibodies to Toxocara. Among the 30,930 persons selected for the survey, 82% (N = 25,733) were interviewed, and 91% (N = 23,527) of those interviewed underwent physical examination of which 87% (N = 20,395) were tested. The age adjusted Toxocara seroprevalence was 13.9% (95% confidence intervals [CI] 12.5, 15.3), and was higher in non-Hispanic blacks (21.2%) than non-Hispanic whites (12%) or Mexican Americans (10.7%; P < 0.001). Increased Toxocara seropositivity was associated with head of household level of education (low versus high) (odds ratio [OR]: 2.2; CI: 1.8, 2.8), poverty (OR: 1.5; CI: 1.3, 1.8), elevated blood lead concentrations (OR: 1.4; CI: 1.1, 1.9), and dog ownership (OR: 1.2; CI: 1.1, 1.4). Toxocara infection is widespread and associated with specific risk groups.

Toxoplasma gondii and Toxocara spp. infections can cause systemic and ocular disease. To estimate the prevalence of infection with these organisms, we tested serum samples from persons > or = 12 years of age obtained in the Third National Health and Nutrition Examination Survey (1988-1994). Among those tested for both T. gondii and Toxocara spp. (n = 16,646), the age-adjusted T. gondii antibody prevalence was 23.6% (95% confidence limit [CL] = 22.1-25.1%) and the Toxocara spp. antibody prevalence was 14.0% (95% CL = 12.7-15.4%). Multivariate analysis controlling demographic and risk factors showed that persons infected with Toxocara spp. were more likely to be infected with T. gondii (odds ratio [OR] = 1.93, 95% CL = 1.61-2.31), and similarly, persons infected with T. gondii were more likely to be infected with Toxocara spp. (OR = 1.91, 95% CL = 1.59-2.28). Infection with T. gondii and Toxocara spp. are common and can be prevented by many similar interventions.

Toxoplasma gondii can cause congenital, neurologic, ocular, and mild or asymptomatic infection. To determine the U.S. prevalence of T. gondii infection, we tested sera collected from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 for T. gondii immunoglobulin G antibodies in persons 6-49 years old and contrasted the results to those comparable in NHANES III (1988-1994) (ages 12-49 years). Of the 17,672 persons examined in NHANES 1999-2004, 15,960 (90%) were tested. The age-adjusted T. gondii seroprevalence among persons 6-49 years old was 10.8% (95% confidence limits [CL] 9.6%, 11.9%), and among women 15-44 years old, 11.0% (95% CL 9.5%, 12.4%). T. gondii seroprevalence declined from 14.1% to 9.0% (P < 0.001) from NHANES III to NHANES 1999-2004 among U.S.-born persons ages 12-49 years. Although T. gondii infects many persons in the U.S., the prevalence has declined in the past decade.

To determine the prevalence and risk factors for Toxoplasma gondii infection in Guatemalan children, in 1999 and 2003 we surveyed caretakers and serologically tested children in the San Juan Sacatepequez area using Platelia Toxo IgG TMB enzyme immunoassay kits. In 1999, of 532 children six months to two years old, 66 (12.4%) were antibody positive. In 2003, in 500 children 3-10 years old antibody prevalence increased from 24% to 43% at age five years then leveled off. By multivariate analysis, drinking well water (relative risk [RR] = 1.78, 95% confidence limit [CL] = 1.00, 3.17, P = 0.05) and not cleaning up cat feces (RR = 2.06, 95% CL = 1.00, 4.28, P = 0.05) increased the risk of T. gondii seropositivity. Most T. gondii infections in children from these villages occurred by age five, but half were still not infected by adolescence. Therefore, it is important to educate girls entering child-bearing age about the risks of acute T. gondii infection and the local risk factors for infection.

In August 2000, the Ohio Department of Health requested assistance to investigate a cryptosporidiosis outbreak with more than 700 clinical case-patients. An epidemiologic and environmental investigation was conducted. Stool specimens, pool water, and sand filter samples were analyzed. A community-based case-control study showed that the main risk factor was swimming in pool A (odds ratio [OR] = 42, 95% confidence interval [CI] = 12.3-144.9). This was supported by results of polymerase chain reaction (PCR) analysis, which showed the presence of both the human and bovine genotypes of Cryptosporidium parvum in case-patients and samples from the filter of pool A. A pool-based case-control study indicated that the highest risk was related to exposure to pool water via the mouth (OR = 5.1, 95% CI = 2.1-12.5) or to pool sprinklers (OR = 2.5, 95% CI = 1.3-4.7). Fecal accidents at the pool were documented. Records indicated that the pool met local health regulations. The outbreak, caused by co-infection with two C. parvum genotypes (human and bovine), underscores the need for concerted action to improve public health policies for recreational water facilities and enhanced education regarding the potential for disease transmission through pools.