Tropical Parasitology最新文献

Background: The escalation of insecticide resistance across the World Health Organization (WHO) African region calls for the routine monitoring of insecticide resistance in mosquitoes. While pyrethroids are recommended for use and dichlorodiphenyltrichloroethane (DDT) has been prescribed, it is imperative to reevaluate their efficacy across diverse geographical settings. The extent of resistance among mosquitoes to DDT and lambda-cyhalothrin remains understudied in Ika North East, Delta State, Nigeria, where the yellow fever virus was reported in 2019.

Materials and methods: We investigated the susceptibility of female mosquitoes to DDT (4%) and lambda-cyhalothrin (0.05%) in this specific study area. Adult female mosquitoes of Anopheles gambiae, Culex quinquefasciatus, and Aedes albopictus, aged between 2 and 4 days, were subjected to these insecticides utilizing the WHO bioassay method. The assessment of knockdown was done between 10 and 60 min, then mortality after 24 h.

Results: C. quinquefasciatus and A. albopictus mosquitoes exposed to DDT and lambda-cyhalothrin exhibited high susceptibility, resulting in complete mortality (100%); however, A. gambiae displayed resistance, with mortality rates of 19% and 76%, respectively . Notably, A. gambiae mosquitoes exposed to piperonyl butoxide (PBO)-DDT and PBO-lambda-cyhalothrin exhibited enhanced mortality, reaching 95% (indicating suspected resistance) and 100% (indicating susceptibility), respectively. Knockdown time (KDT) for 50% in mosquitoes exposed to lambda-cyhalothrin ranged from 3.94 to 33.51 min. Similarly, KDT model for 95% ranged from 19.04 to 84.15 min. Among the tested mosquito species, Culex mosquitoes exhibited the shortest knockdown resistance time for lambda-cyhalothrin, recorded at 3.94 min. Similarly, the KDT for DDT ranged from 24.97 to 187.06 min for 50% mortality and from 61.04 to 431.03 min for 95% mortality, respectively. Anopheles mosquitoes exposed to PBO + DDT recorded the lowest KDT.

Conclusion: Our study underscores the potential of exercising caution in the use of DDT and lambda-cyhalothrin insecticides for the control of mosquitoes due to emerging resistance.

Cysticercosis is one of the most common parasitic infections seen in the human population which most commonly affects the nervous system. Isolated cysticercosis of the liver is rare, and only less than five cases have been reported in the literature. Here, we describe an isolated cysticercosis of the liver. The cyst appeared as a firm nodule on the surface of the liver during a prepyloric perforation repair. The biopsy of the nodule revealed a cyst wall, and a contrast-enhanced computed tomography postoperative showed cysts in the liver. The patient was further evaluated with whole-body imaging which did not reveal any other cysts elsewhere.

Cryptosporidium species cause watery diarrhea in several vertebrate hosts, including humans. Most apparently, immunocompetent-infected individuals remain asymptomatic, whereas immunocompromised may develop severe or chronic cryptosporidiosis. We report here the case of a 6-year-old girl undergoing chemotherapy for Burkitt lymphoma who experienced multiple episodes of watery diarrhea during her hospital stay. Microscopic examination of her stool sample revealed oocysts of Cryptosporidium species. The rapid immunochromatographic test was also positive for Cryptosporidium species. She was treated with nitazoxanide for 3 weeks, which failed to provide both clinical improvement and parasitological clearance. This case highlights the importance of treatment failure in human cryptosporidiosis.

Purpose: As we edge closer to the eradication of malaria, several methods for detecting Plasmodium species have been developed, including peripheral blood smear examination (PBS), rapid diagnostic tests (RDTs), serological evaluations, fluorescent microscopy, polymerase chain reactions (PCRs), fluorescent in situ hybridization, and flow cytometry. The suitability of these tools for routine diagnosis requires evaluation, considering both their diagnostic accuracy and cost-effectiveness.

Materials and methods: Our study compared four diagnostic techniques for malaria: PBS, quantitative buffy coat (QBC), RDT, and PCR. We used PCR as the benchmark standard and statistically assessed the performance of PBS, QBC, and RDT against PCR in detecting malaria. Adopting a prospective observational approach, we collected blood samples from 117 patients exhibiting the symptoms suggestive of malaria.

Results: The findings from our study showed that PBS had a positivity rate of 93.4%, with a 95% confidence interval (CI) of 0.881-0.987, indicating reliable results for a similar population. The QBC assay demonstrated an elevated positivity rate of 96.7% with a solid 95% CI of 0.930-1.000. Although the RDT had a slightly lower rate of 92.4%, it still delivered dependable results, presenting a significant 95% CI of 0.868-0.980, ensuring a robust diagnostic performance compared to PCR.

Conclusion: PCR is a reliable test when the identification of the specific species is inconclusive. Conversely, the commonly used PBS occasionally overlooks positive malaria cases due to the specialized skills needed for accurate reading. The cost-effective RDT is feasible for field operations without the need for expert knowledge. However, it fails to differentiate between old and new infections. Meanwhile, the QBC test, known for its sensitivity and speed, can be consistently employed for malaria diagnosis in a tertiary care settings.

Background: Giardia intestinalis is an intestinal protozoan which commonly causes parasitic gastroenteritis globally. It is a species complex consisting of at least eight assemblages (genotypes). In India, Giardia is mostly underreported and missed in asymptomatic cases.

Aim: The aim of this study was to genotype the G. intestinalis isolates from stool samples of patients at a tertiary care center in Rajasthan, India, and to clinically correlate it.

Methods: This prospective pilot cross-sectional study was conducted from 2019 to 2021 in a tertiary care center in western India. Patients who were microscopically positive for giardiasis were enrolled. DNA was extracted from their stool samples and amplified by polymerase chain reaction (PCR) using 4E1-HP as the target sequence. Anthropometric measurements and analysis were done for children by using Anthrocal application.

Results: A total of 50 patients were enrolled. Diarrhea was present in 18 patients (36%). Among these, 6 were immunocompromised and had different comorbidities. Among the children <12 years of age, 55.17% (n = 16/29) were stunted (<-2 S.D.), and among <5 years, 44.4% (n = 4/9) showed wasting (<-2 S.D.). A PCR product corresponding to assemblage B of G. intestinalis was amplified in 47 stool specimens. Only three stool samples were negative for both assemblages A and B and posed an interesting enigma.

Conclusion: In this study, a predominance of assemblage B of G. intestinalis was detected in 94% of the isolates. Furthermore, the possibility of zoonotic transmission could not be ruled out.