Tropical Parasitology最新文献

Background: Visceral leishmaniasis (VL) is a parasitic disease that affects public health. It is described by weight reduction, irregular fever bouts, anemia, and amplification of the spleen and liver.

Materials and methods: Three concentrations (15.6, 31.2, and 62.5 μg/mL) were used to find the potency of an aqueous extract of Chara vulgaris algae in the treatment of VL. A cytotoxicity assay was performed to show the cytotoxic effect of this extract on human cells. High-performance liquid chromatography (HPLC) test was done to determine the active compounds in the extract. Histopathological sections for infected liver and spleen were performed, as were liver function tests (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase), which were assessed after 1 month of treatment.

Results: As cytotoxicity assay, results showed that there were no significant differences between the cells treated and those not treated with the extract. HPLC test demonstrated that phenolic and terpene compounds are the main active compounds in the extract. P-coumaric acid and ursolic acid present the highest percent among other phenolic and terpene compounds (21.84%, 17.82%), respectively. Histopathological sections showed that this extract had a significant effect in the treatment of infected tissues, and this effect was very clear after the end of the treatment period. As for the liver function tests, a significant increase (P < 0.01) in the studied liver enzymes was found in the infected group of mice compared to the healthy group, whereas in the infected and treated groups, a clear and gradual decrease in the level of enzymes was observed.

"Human dirofilariasis, caused by filarial worms of the genus Dirofilaria, is considered an emerging zoonotic filarial infection transmitted to humans by zoo-anthropophilic blood-sucking insects. The most common Dirofilaria species causing human infections include Dirofilaria repens and Dirofilaria immitis. In this case report, we present the case of a 60-year-old male patient who reported the presence of an intraoral swelling in the right maxillary vestibular region. Upon excision of the lesion and further microscopic and histological examination, a female Dirofilaria was identified as the causative agent."

The target of kala-azar elimination was initially set in 2010 and was later extended several times to finally be fixed in 2020, which also passed without success. However, in 2022, India had come very close to complete elimination by achieving a 98.7% decline in kala-azar cases. While, at the final moments of achieving the long-awaited target of elimination of kala-azar from India, the unexpected rise in the case-fatality rate from 2017 needs to be addressed.

Introduction: Free-living amoeba is ubiquitous in fresh water, mud, and moist soil; although seldom pathogenic to humans, Naegleria fowleri, Acanthamoeba spp., and Balamuthia spp. are known to cause infections of the central nervous system.

Methods: We report two interesting cases, both of which presented with a rapid-onset and fulminant course. The first case details a 36-year-old male with a history of surgically corrected nasal bone fracture 15 years back, who presented with acute onset of fever, headache and convulsions.

Results: Direct smears of cerebrospinal fluid (CSF) revealed motile trophozoites resembling N. fowleri and were later confirmed by molecular diagnosis (polymerase chain reaction [PCR]). Subsequently, the source was identified as water used for religious purposes. Unfortunately, the patient succumbed to cardiac arrest. The second case is that of a 4-year-old boy from Palakkad district, Kerala, who presented with sudden onset of nasal discharge, fever, headache, vomiting, seizures and altered sensorium. His CSF smear examination showed motile trophozoites resembling Acanthamoeba spp. While undergoing treatment, he seized thrice before going into cardiac arrest. Despite extensive resuscitation measures, the child could not be revived and passed away. The postmortem CSF sample sent for molecular analysis confirmed infection by Acanthamoeba spp.

Conclusion: Rapid progression and lack of definite treatment options make this a highly fatal condition. Although clinical presentations of both patients were indicative of pyogenic meningitis, parasitic infection was suspected when the CSF was found turbid with no bacteria, high protein, and low sugar. High index of suspicion helped us to get an early preliminary diagnosis from direct microscopy.

Intestinal parasitic infections (IPIs) are a major health concern in resource-limited countries of South/South-East Asian region. Despite posing a potential threat to maternal and fetal health, there is limited data available on the actual burden of IPI among pregnant women. Through this systemic review and meta-analysis, we sought to determine the pooled prevalence of IPI and species-specific prevalence among pregnant women in this region. Subgroup analysis was done by region, stool examination technique, and study settings. Among 220 retrieved studies, 21 studies from 8 countries across the region were found eligible and included in this study. The estimated overall pooled prevalence of IPIs among pregnant women was 43.15% (95% confidence interval: 30.66-56.10). The most prevalent IPI was Ascaris lumbricoides (25.14%) and predominant protozoa was Entamoeba histolytica/dispar (6.96%). In subgroup analysis, the estimated pooled prevalence of IPIs in Nepal, India, Thailand, and Thai-Burmese Border was 40.88%, 28.33%, 55.38%, and 23.78%, respectively. Studies using Kato-Katz technique for stool examination showed the highest estimated pooled IPI prevalence (62.70%). The prevalence of IPI was found to be lower in facility-based studies (38.12%) than that of studies done in the community (66.21%). Considering the high burden of IPI in pregnant women as estimated in our review and the already established impact of IPI infection on maternal health and fetal outcomes, we recommend implementation of the preventive chemotherapy during routine antenatal checkups.

Background: Soil-transmitted infections such as Ascaris lumbricoides, Hookworm, Trichuris trichiura, and Strongyloides stercoralis are common in South India. Factors such as diet, sanitation, and living conditions play a role in the prevalence of helminthic diseases. Many individuals remain asymptomatic carriers. Timely intervention is essential to prevent these infections.

Materials and methods: This is a prospective, randomized intervention study that enrolled 52 participants, excluding children, all of whom had parasitic infections. A prevalidated questionnaire was given to assess the risk factors for parasitic diseases, and fecal examinations were conducted to identify parasitic infestations. The World Health Organization's hand hygiene self-assessment framework was used to evaluate handwashing skills. Subsequent posttesting and resampling of patients allowed for score comparison, assessment of reductions in parasitic load, determination of cure rates, and monitoring of patient readmission rates.

Results: After the health education intervention, a statistically significant improvement (P < 0.01) was observed in patients' knowledge and attitudes toward parasitic infections, as shown by their posttest scores compared to their pretest scores. In addition, there were notable improvements in handwashing skills following the implementation of the handwashing educational program.

Conclusion: This research confirms that health education is vital in promoting proper hand hygiene, reducing parasitic infections, and urging timely medical care for these conditions.

Elephantiasis, also known as filariasis, is a severe public health issue in India. Microfilariae in the bone marrow smears are an unusual and incidental finding. Every peripheral blood and bone marrow aspirate smear must be screened for microfilariae in endemic areas to identify asymptomatic carriers. Here, we report a case of a 50-year-old man who presented with pyrexia of unknown origin. He had mild pallor and right-side inguinal lymphadenopathy. Peripheral blood showed anemia and leukocytosis with neutrophilia. Other serological tests, radiological examination, and aspiration cytology from the lymph node were inconclusive. The bone marrow aspirate smears incidentally displayed microfilaria, and the inguinal lymph node demonstrated an adult filaria worm. The association of microfilaria infection with pyrexia of unknown origin (PUO) and peripheral blood neutrophilia has been rarely reported in the literature. The patient recovered from fever and weakness with antifilarial medication and hematinics.

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.