Acta tropica最新文献

Various bat species worldwide have been identified as Leptospira carriers, especially in tropical regions. In this study, we investigated the infection of Vespertilionidae bats by pathogenic Leptospira in north-west Russia. Out of 264 bats from 13 species, the urine of 24 specimens tested positive according to a polymerase chain reaction test. The infected species were exclusively Myotis bats: M. brandtii (1/56; 1.8 %); M. dasycneme (9/40; 22.5 %); and M. daubentonii (14/47; 29.8 %). The detected Leptospira strains were similar to L. kirschneri and L. borgpetersenii.

Protective efficacy assessment of toxoplasmosis vaccines, at least at the preclinical level, frequently involves lethal dose challenge infection. Nonetheless, their efficacies remain largely unexplored against low infection doses which better reflects how humans become infected in the real world. In this study, we compared the immunity elicited in mice that were heterologously immunized with recombinant baculovirus and virus-like particles expressing either the cyst wall protein (CST1) or microneme protein 8 (MIC8) of Toxoplasma gondii (T. gondii). We also investigated how these vaccines fared against both light and heavy infection intensities of T. gondii ME49. Interestingly, under light infection intensity, vaccines expressing CST1 induced significantly higher mucosal antibody responses than MIC8. Germinal center B (GC B) cell responses were elicited to a greater extent following immunization with either antigen, regardless of the infection dose. Similarly, both antigens suppressed IFN-γ production in the brains upon heavy infection. The overall vaccine-induced protection was also similar for the two vaccine antigens under heavy infection. However, in lightly infected mice, CST1 conferred improved GC B cell induction and further inhibited IFN-γ and cyst burden than those elicited by MIC8, thereby contributing to better protection. These findings indicated that light infection could be used to identify optimal vaccine candidates, thus highlighting the impact of infection intensity in vaccine efficacy evaluations.

Background: Trichomonas vaginalis (T. vaginalis) is a common sexually transmitted parasite that colonizes the human urogenital tract. Programmed and precise detection of T. vaginalis is a key step in preventing and treating trichomoniasis. However, the current detection methods of T. vaginalis, including wet mount microscopy, culture, nested PCR, loop-mediated isothermal amplification, and recombinant enzyme polymerase amplification, have some shortcomings. Therefore, it is urgent to establish a programmed, sensitive, and specific method for detecting T. vaginalis.

Methods: T. vaginalis cysteine protease 39 (TvCP39) was expressed in segments as TvCP39-1 and TvCP39-2, and the polyclonal antibodies were prepared by immunizing rats and rabbits. The concentration of the polyclonal antibodies of anti-rTvCP39-2 and anti-rTvCP39-1 was determined by square matrix titration. The sensitivity and specificity of double antibody sandwich ELISA were analyzed and evaluated by detecting rTvCP39 and T. vaginalis excretory-secretory proteins (TvESPs) diluted in multiple ratios and detecting excretory-secretory proteins of T. vaginalis and other pathogens, respectively. The detection efficiency of wet mount microscopy, nested PCR, and double antibody sandwich ELISA was compared by testing sixty-two clinical samples from vaginal secretions.

Results: The natural TvCP39 protein could be specifically recognized by anti-rTvCP39-1 and anti-rTvCP39-2 antibodies. The concentrations of anti-rTvCP39-2 and anti-rTvCP39-1 polyclonal antibodies were determined to be 0.58 μg/mL and 0.45 μg/mL, respectively. The results of the sensitivity test showed that the detection limits of rTvCP39 and TvESPs by double antibody sandwich ELISA were 1.76 ng/mL and 107.125 μg/mL, respectively. The specificity test results showed that the double antibody sandwich ELISA had a high specificity for the detection of T. vaginalis and did not cross-react with Escherichia coli, Staphylococcus aureus, Candida albicans, and Lactobacillus. The positive detection rate of clinical samples by double antibody sandwich ELISA was higher than that by wet mount microscopy, and was the same as nested PCR. The sensitivity of double antibody sandwich ELISA was consistent with that of nested PCR. The coincidence rate between double antibody sandwich ELISA and nested PCR was 100% (Kappa=1, P < 0.001).

Conclusion: The double antibody sandwich ELISA detection method for T. vaginalis established in this study had the advantages of high sensitivity and specificity, and did not require the extraction of genomic DNA. This programmatic and simple detection method was suitable for batch testing of clinical samples and exhibited the potential value in the treatment and prevention of trichomoniasis.

Brucellosis remains a major public health challenge in China and globally. This study analyzed long-term trends in brucellosis incidence in China from 2006 to 2020, assessed the effects of age, period, and birth cohort, and projected future incidence up to 2030. Data on brucellosis were obtained from the Data-center of China Public Health Science, and temporal trends in incidence rates were analyzed using joinpoint regression, while an age-period-cohort model evaluated the effects of age, period, and cohort. A Bayesian age-period-cohort model was applied for future projections. From 2006 to 2020, 586,371 brucellosis cases were reported, with an upward trend in age-standardized incidence rates for both males and females, showing average annual percent changes of 3.37 % and 4.61 %, respectively. The age-period-cohort model revealed that age, period, and cohort all influenced incidence, with males facing higher rates. High-risk groups were identified among those aged 50-84, particularly in the 65-69 age range, where incidence was highest and showed the most significant annual increase. Period risk initially rose then declined, while later-born cohorts had higher risks. Projections indicate a continued rise in brucellosis incidence. Targeted prevention and control measures are recommended, especially for older adults and males.