[Show abstract][Hide abstract] ABSTRACT: Human babesiosis, a blood-borne infection caused by several species of Babesia, including B. microti, is an emerging disease that is endemic in the Northeast, upper Midwest, and Pacific Northwest regions of the United States. Risk factors for babesiosis include exposure to the infected tick vector and blood transfusions from infected donors. In this work, we cloned and expressed two of the immunodominant antigens from B. microti and used them in a multiplex bead format assay (MBA) to detect parasite-specific IgG responses in human sera. The MBA using recombinant B. microti secreted antigen 1 (BmSA1) protein was more specific (100%) and slightly more sensitive (98.7%) than the assay using a truncated recombinant BMN1-17 construct (97.6% and 97.4%, respectively). Although some antibody reactivity was observed among sera from confirmed-malaria patients, only one Plasmodium falciparum sample was simultaneously positive for IgG antibodies to both antigens. Neither antigen reacted with sera from babesiosis patients who were infected with Babesia species other than B. microti. Both positive and negative MBA results were reproducible between assays and between instruments. Additional studies of these recombinant antigens and of the multiplex bead assay using blood samples from clinically defined babesiosis patients and from blood donors are needed to more clearly define their usefulness as a blood screening assay.
[Show abstract][Hide abstract] ABSTRACT: 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.
The American journal of tropical medicine and hygiene 01/2008; 78(1):35-9. · 2.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated changes in hematologic and biochemical parameters associated with human T lymphotropic virus type 1 (HTLV-1) infection, antibody titer, and provirus load. Additionally, on a subset of participants, we assessed the epidemiologic relationship of HTLV-1 with Strongyloides stercoralis.
Among volunteer blood donors in Jamaica, HTLV-1 carriers (n=482) were frequency matched with HTLV-1 negative subjects (n=355) by age (+/-5 years), sex, and date of blood donation (+/-3 months). HTLV-1 antibody titer, provirus load, S. stercoralis IgG antibodies, complete blood cell count, blood chemistry, and urinalysis parameters were measured.
HTLV-1 carriers, compared with HTLV-1-negative individuals, had elevated levels of cleaved lymphocytes (24.5% vs. 16.4%), any lymphocyte abnormalities (atypical, cleaved, and reactive lymphocytes combined, 45.7% vs. 35.4%), and gamma-glutamyl transferase levels (21.2 vs. 19.6 IU/L), as well as lower eosinophil count (2.6% vs. 3.1%). Among carriers, HTLV-1 antibody titer (n=482) was inversely correlated with mean corpuscular volume (r=-0.10) and positively correlated with levels of total protein (r=0.16), phosphorus (r=0.12), and lactate dehydrogenase (r=0.24). HTLV-1-provirus load (n=326) was higher among carriers with cleaved lymphocytes and any lymphocyte abnormalities. Provirus load was inversely correlated with hemoglobin (r=-0.11), mean corpuscular volume (r=-0.15), neutrophil (r=-0.12), and eosinophil (r=-0.19) levels and was positively correlated with lactate dehydrogenase levels (r=0.12). Provirus load was significantly higher among male than female subjects. S. stercoralis antibodies were detected in 35 (12.1%) of 288 participants but were not associated with HTLV-1 status, antibody titer, or provirus load.
Markers of HTLV-1 infection (infection status, antibody titer, and provirus load) are associated with hematologic and biochemical alterations, such as lymphocyte abnormalities, anemia, decreased eosinophils, and elevated lactate dehydrogenase levels.
[Show abstract][Hide abstract] ABSTRACT: Schistosomiasis and strongyloidiasis cause substantial morbidity and mortality among hundreds of millions of infected persons worldwide. In the United States, these infections are most commonly found among international travelers, immigrants, and refugees from areas of endemicity. Refugees resettled to the United States since 2000 include >3800 "Lost Boys and Girls" of Sudan and 8000 Somali Bantu. Many Lost Boys and Girls of Sudan reported chronic abdominal pain only since arrival, and some received diagnoses of schistosomiasis or strongyloidiasis. We assessed seroprevalence of these infections among these refugees and hypothesized an association between infection and abdominal pain.
We offered a survey assessing chronic abdominal pain and serologic testing for schistosomiasis and strongyloidiasis to all 800 attendees of a Lost Boys and Girls of Sudan reunion in the United States. Serologic testing was performed on preimmigration specimens obtained from 100 United States-bound Somali Bantu refugees.
Of the 462 Sudanese refugees (58%) tested, 44% and 46% were seropositive for schistosomiasis (primarily due to Schistosoma mansoni) and strongyloidiasis, respectively; 24% of those who tested positive for schistosomiasis had S. mansoni antigenemia. Forty-six percent reported chronic abdominal pain, which was not associated with either infection. Among 100 Somali Bantu, 73% and 23% tested seropositive for schistosomiasis (primarily due to Schistosoma haematobium) and strongyloidiasis, respectively.
The high seroprevalence of schistosomiasis and strongyloidiasis among Sudanese Lost Boys and Girls and Somali Bantu refugees supports presumptive treatment for these refugees. Current refugee resettlement policies inadequately address these diseases; our data support consideration of predeparture presumptive therapy for all refugees from areas of endemicity.
[Show abstract][Hide abstract] ABSTRACT: 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.
The American journal of tropical medicine and hygiene 09/2007; 77(3):405-10. · 2.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Schistosomiasis and strongyloidiasis cause substantial morbidity and mortality among the millions of infected persons worldwide. In the U.S., these diseases are found most frequently among the 28,000 refugees and hundreds of thousands of other immigrants resettled annually.
Prevalence in such groups is unknown because of infrequent testing and use of insensitive stool and urine examinations. Using sensitive serologic tests, we assessed infection rates among some of the 3,800 resettled Lost Boys of Sudan (LBOS) during an evaluation of abdominal pain at a national reunion and subsequently among a group of Somali Bantu refugees.
Methods: All consenting LBOS answered questions about symptoms and were tested by enzyme immunoassays for antibodies to Schistosoma and Strongyloides, and a Schistosoma mansoni antigen assay. Randomly selected Somali Bantus underwent similar testing.
Results: Of 462 LBOS, 203 (43.9%) and 214 (46.3%) were seropositive for schistosomiasis and strongyloidiasis, respectively. Forty-eight (10.4%) had S. mansoni antigenemia, indicating active infection of at least moderate intensity. By immunoblot, S. mansoni was more common then Schistosoma haematobium or mixed infections in a randomly selected subset of 21 persons. Although 214 (46.3%) reported abdominal pain, no association was seen between this or other symptoms and schistosomiasis or strongyloidiasis.
Among 100 Somali Bantus, 73 (73.0%) and 23 (23.0%) were seropositive for schistosomiasis and strongyloidiasis, respectively. The predominant schistosome species by immunoblot was S. haematobium.
Conclusions: The high seroprevalence of schistosomiasis and strongyloidiasis and evidence of active infection support presumptive treatment of all LBOS and Somali Bantus refugees. Such serologic testing could also be used to estimate infection rates and need for presumptive treatment among other refugee populations. Current immigration policies inadequately address testing and treatment for these diseases; our data support reevaluation of such policies for all immigrants from Schistosoma or Strongyloides endemic areas.
Infectious Diseases Society of America 2005 Annual Meeting; 10/2005
[Show abstract][Hide abstract] ABSTRACT: 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.
The American journal of tropical medicine and hygiene 04/2005; 72(3):295-300. · 2.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To gain knowledge about laboratory testing practices for parasitic diseases, in 2000 we surveyed 562 laboratories in 9 US states, and 455 (81%) responded. Most laboratories (59%) indicated that they send specimens off site for parasite screening, and most laboratories (89%) did not routinely test fecal specimens for Cryptosporidium species, Cyclospora cayetanensis, or microsporidia, unless testing for these organisms was specifically requested by a physician. Only 39 laboratories offered serological testing for Toxoplasma gondii, and most (78%) that had their results confirmed did so at national commercial laboratories rather than a Toxoplasma reference laboratory. Because most clinical laboratories do not routinely test fecal specimens for Cryptosporidium species, C. cayetanensis, or microsporidia, physicians must request specific testing for these organisms when they are clinically suspected; because of this lack of routine testing, it is difficult to estimate the true burden of disease due to these organisms.
[Show abstract][Hide abstract] ABSTRACT: Infection with Toxoplasma gondii can lead to congenital and acquired disease, resulting in loss of vision and neurologic illness. We tested sera collected in the National Health and Examination Survey (NHANES) from 1999-2000 for T. gondii-specific immunoglobulin G antibodies and compared these results with results from sera obtained in the NHANES III survey (1988-1994). NHANES collects data on a nationally representative sample of the U.S. civilian population. Of 4,234 persons 12-49 years of age in NHANES 1999-2000, 15.8= (age-adjusted, 95% confidence limits [CL] 13.5, 18.1) were antibody positive; among women (n = 2,221) 14.9= (age-adjusted, 95% CL 12.5, 17.4) were antibody positive. T. gondii antibody prevalence was higher among non-Hispanic black persons than among non-Hispanic white persons (age-adjusted prevalence 19.2% vs. 12.1%, p = 0.003) and increased with age. No statistically significant differences were found between T. gondii antibody prevalence in NHANES 1999-2000, and NHANES III. T. gondii antibody prevalence has remained stable over the past 10 years in the United States.
[Show abstract][Hide abstract] ABSTRACT: Approximately 85 percent of women of childbearing age in the United States are susceptible to acute infection with the protozoan parasite Toxoplasma gondii. Transmission of T. gondii to the fetus can result in serious health problems, including mental retardation, seizures, blindness, and death. Some health problems may not become apparent until the second or third decade of life. An estimated 400 to 4,000 cases of congenital toxoplasmosis occur in the United States each year. Serologic tests are used to diagnose acute T. gondii infection in pregnant women. Because false-positive tests occur frequently, serologic diagnosis must be confirmed at a Toxoplasma reference laboratory before treatment with potentially toxic drugs is considered. In many instances, congenital toxoplasmosis can be prevented by educating pregnant women and other women of childbearing age about not ingesting raw or undercooked meat, using measures to avoid cross-contamination of other foods with raw or undercooked meat, and protecting themselves against exposure to cat litter or contaminated soil.
American family physician 06/2003; 67(10):2131-8. · 1.82 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although the incidence of toxoplasmosis is low in the United States, up to 6000 congenital cases occur annually. In September 1998, the Centers for Disease Control and Prevention held a conference about toxoplasmosis; participants recommended a survey of the toxoplasmosis-related knowledge and practices of obstetrician-gynecologists and the development of professional educational materials for them.
In the fall of 1999, surveys were mailed to a 2% random sample of American College of Obstetricians and Gynecologists (ACOG) members and to a demographically representative group of ACOG members known as the Collaborative Ambulatory Research Network (CARN). Responses were not significantly different for the random and CARN groups for most questions (p value shown when different).
Among 768 US practicing ACOG members surveyed, 364 (47%) responded. Seven per cent (CARN 10%, random 5%) had diagnosed one or more case(s) of acute toxoplasmosis in the past year. Respondents were well-informed about how to prevent toxoplasmosis. However, only 12% (CARN 11%, random 12%) indicated that a positive Toxoplasma IgM test might be a false-positive result, and only 11% (CARN 14%, random 9%) were aware that the Food and Drug Administration sent an advisory to all ACOG members in 1997 stating that some Toxoplasma IgM test kits have high false-positive rates. Most of those surveyed (CARN 70%, random 59%; chi2 p < 0.05) were opposed to universal screening of pregnant women.
Many US obstetrician-gynecologists will encounter acute toxoplasmosis during their careers, but they are frequently uncertain about interpretation of the laboratory tests for the disease. Most would not recommend universal screening of pregnant women.
Infectious Diseases in Obstetrics and Gynecology 01/2001; 9(1):23-31. DOI:10.1155/S1064744901000059