Congenital human toxoplasmosis caused by non-clonal Toxoplasma gondii genotypes in Argentina

Toxoplasmosis, a worldwide distributed zoonosis, can be transmitted congenitally affecting fetuses and developing variable clinical signs. Different Toxoplasma gondii genotypes and infective dose are related factors with different clinical manifestations. Several studies indicate that atypical strains could produce more severe clinical manifestations compared to typical strains. Umbilical cord blood (n = 37) and placenta (n = 19) were collected at birth from women with acute T. gondii infection and processed for isolation by mice bioassay. Six isolates were obtained and identified as TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg, TgHm17-01Arg and TgHm17-02Arg. Three genotypes described previously on Toxo-DB were identified: #138 identified in chickens from Brazil, #182 isolated from eared doves from Brazil, #14 from wallaby kangaroos and chickens from Argentina, chickens from Brazil, Colombia, Chile and Venezuela, cats and dogs from Brazil and Colombia and also coyotes from USA indicating worldwide distribution of these genotypes. Two new allele combinations were obtained showing high genotypes diversity in Argentina. Four of the isolates (TgHm14-4Arg, TgHm15-02Arg, TgHm16-01Arg, TgHm16-02Arg) and two of them (TgHm17-01Arg, TgHm17-02Arg) produced chronic and acute infections in mice, respectively. Until now, seven T. gondii isolates have been obtained from humans in Argentina, and all were atypical or non-clonal genotypes. The identification of atypical strains causing congenital toxoplasmosis and circulating in our region, make important to perform the serological screenings according Argentine Consensus of Toxoplasmosis and to apply and monitoring treatments earlier in pregnancy. To achieve this aim, it is necessary to inform general population about T. gondii infection, diagnostics and control measures. These results should serve to generate awareness about congenital toxoplasmosis in South America.

[Prevalence of anti-Toxoplasma gondii antibodies in blood donors in Buenos Aires city, from 1967 to 2017]

A prevalence study of antibodies anti Toxoplasma gondii in voluntary blood donors who attended the hemotherapy service at the Hospital Alemán during the first four months of the years 1997, 2007 and 2017 was carried out and the results were compared to the study carried out in 1967. The sera where processed with the Sabin Feldman Dye Test. The global average seroprevalence in 1967 was 67.0% (CI95%, 64.4%-69.6%); in 1997, 35.0% (CI95%, 33.3%-38.3%); in 2007, 31.9% (CI95%, 29.6%-34.2%) and in 2017, 21.2% (CI95%, 19.0%-23.3%). In the fifty years covered by the study the decline in prevalence was 45.8%, which represents an average annual decline of 0.9%.The decline was statistically significant between 1967 and 1997, and between 2007 and 2017. The four studies demonstrate that infection prevalence increased depending on age. The infection rate for 1967 was 1.0% per year and declined in the next studies to 0.8% in 1997, 0.8% in 2007, and 0.5% in 2017. Donors from the last study responded to a survey that showed a statistically significant correlation between seroprevalence of Toxoplasma gondii antibodies and lack of tap water, unfinished secondary studies or residence in the western or southern part of the Buenos Aires metropolitan area. No significant association was found with having a cat as a pet, the consumption of undercooked meat or the practice of gardening.

Ten-year persistence of antibody to hepatitis B surface antigen in healthcare workers vaccinated against hepatitis B virus, and response to booster vaccination

This study estimated the number of HCWs with protective antibody levels 5 and 10 years after HBV vaccination. Kaplan-Meier probabilities of protective levels were 0.95 at 60 days after vaccination, 0.87 at 5 years, and 0.79 at 10 years. Those without protective levels displayed good response 7 and 30 days after a booster.