Parasitology最新文献

Loiasis is widespread in Central Africa. Some acute symptoms are associated with high Loa loa microfilaraemia, but the relation between the latter and the adult worm burden infecting an individual with loiasis is still unclear. This study aims to determine whether polyinfection by several reproductive female worms could be assessed using genetic variation in the mitochondrial genome of microfilariae. Microfilariae were collected from the individuals' blood. An optimization of the DNA extraction method that provides enough genetic material and minimization of human host contamination was the first step of the study. Extracted DNA was sequenced using the Illumina platform. Genetic variation in the mitochondrial genome was assessed by identifying polymorphic Single Nucleotide Polymorphisms (SNPs) and estimating the number of haplotypes. Dedicated DNA extraction kits yielded more DNA extracted (mean: 530 ng; SD = 211) from dried blood smears than the in-house chloroform-isoamyl method (mean: 102.5 ng; SD = 118). Filtering the slide elution and venous blood with 5 µm pore size microfilters improved parasite DNA mapping rates (54.64-79.65%). Analysis of polymorphism in the microfilariae mitochondrial genome from three individuals revealed 50, 207 and 332 polymorphic SNPs, respectively. A total of 7 to 20 mitochondrial DNA haplotypes were identified, representing the minimum number of fertile female worms. This study presents the first approach to estimating the L. loa female worm burden and highlights female parent polyinfection in individuals with loiasis.

Paraxerus cepapi is an arboreal tree squirrel that occurs in the Savanna biome of Africa, and information on its parasite diversity is limited and mostly qualitative. The aim of the study was to record the diversity and abundance of ecto- and helminth parasites associated with P. cepapi across its distribution in South Africa. P. cepapi individuals (n = 94) were opportunistically obtained from eight localities during 2020 to 2024. In total, 21 parasite species (19 ectoparasites and two nematodes) and one tick species group were identified. This included lice, ticks, fleas, a mesostigmatic mite, chiggers, nematodes and cestodes. Nematodes were the most prevalent (93·67%), followed by lice (80·85%). Syphatineria cepapi was recorded in 92·41% of P. cepapi, while an unknown Strongyloides species, resembling S. robustus, was recorded in 21·52% of squirrels. The lice species displayed variation in parasitope preference, while chiggers were primarily recorded in the ears. This study provides new country records for the lice species Werneckia paraxeri and Enderleinellus heliosciuri, for the chigger species Microtrombicula polymorpha, and for the nematode S. cf. robustus. New locality records were documented for the nematode S. cepapi in South Africa, and P. cepapi is a new host record for the eight chigger species and S. cf. robustus. It is evident that P. cepapi in South Africa hosts a considerably larger diversity of parasite taxa than previously recorded. Nematode counts were related to host length. These findings warrant future studies on the parasite diversity of P. cepapi in Africa.

Ectoparasites are commonly found on wild birds and might play an important role as vectors of pathogens. The Balearic Islands archipelago (Spain) is an ecological hotspot for wild birds due to its geographical location and habitat diversity. Although the avian fauna of the archipelago is well studied, little information is available regarding the ectoparasites infesting its wild bird populations. This study aimed to identify the diversity of ectoparasites (chewing lice, louse flies and ticks) and feather mites on wild birds in several locations on Menorca Island, as well as to assess the prevalence based on the migration status and season. Our research revealed that ten of the 13 species of chewing lice collected in this study are reported here for the first time in the Balearic Islands, including two that are also new records for Spain. We did not find statistically significant differences in the prevalence of ectoparasites or feather mites between sedentary and migratory birds. Likewise, no significant differences were observed in feather mite prevalence among migratory birds from Illa de s'Aire between prenuptial and postnuptial migrations. This study provides valuable insights into the prevalence and diversity of ectoparasites, shedding light on their potential role as vectors for avian pathogens. Further research is needed to explore the pathogens these ectoparasites may carry and transmit, contributing to a better understanding of the epidemiology of avian diseases in Menorca.

Women in sub-Saharan Africa face complex, multifaceted challenges to their health, including a high burden of infectious diseases aggravated by socioeconomic factors. Parasitic and sexually transmitted infections both cause significant morbidity and mortality. Co-infections compound these effects, leading to high rates of chronic illness and making diagnosis and treatment challenging. There are no integrated approaches for the detection of female genital schistosomiasis (FGS), a gynaecological condition caused by Schistosoma haematobium, and high-risk human papillomavirus (HR-HPV), responsible for over 90% of all cervical cancer cases worldwide. FGS is a chronic condition with health outcomes such as infertility and abortion and remains severely under-reported. HR-HPV infection is the main aetiological agent of cervical cancer, the leading cause of cancer death in women in sub-Saharan Africa. Both can be disabling and stigmatizing to the sufferer. A key to disease management at patient and community levels is accurate and available diagnostics. Due to both FGS and HPV diagnostics utilising cervicovaginal samples, they are ideal candidates for a multiplex molecular diagnostic. The standard molecular diagnostics (namely PCR), through the detection of pathogen DNA, are constrained in low resource settings by requirement of a highly reliable source of energy, reliance on a cold-chain, and prohibitive costs. Isothermal molecular diagnostics are an alternative method to PCR that are more suited to basic settings. This review explores current isothermal diagnostics, with a focus on RPA/RAA, a very simple isothermal technology, for FGS and HPV and proposes the development of a multiplex isothermal diagnostic test to enable integrated screening.

We applied 2 methods of phylogenetic regionalization (evoregions and phyloregions) for the distributions of fleas and their rodent hosts across Mongolia. We investigated the congruence between these 2 regionalization schemes and their alignment with physiographic and ecological subdivisions of Mongolia. We identified evoregions and phyloregions for both fleas and hosts. Ancestral regional distributions were reconstructed, and a phylogenetic correspondence analysis identified key contributing lineages. Using the V-measure, we tested for the congruence between (a) evoregions or phyloregions identified for fleas and evoregions or phyloregions, respectively, identified for their hosts and (b) evoregions and phyloregions identified for either fleas or hosts and each of the physiographic/ecological regionalization schemes of Mongolia. Four evoregions and 8 phyloregions were identified for both fleas and hosts, exhibiting distinct spatial patterns. Host-parasite regionalizations demonstrated moderate spatial similarity (V-measure 0.49-0.50), a significantly higher congruence than previously reported at the larger Palearctic scale (0.33). Flea regionalizations exhibited stronger congruence with environmental schemes than did host regionalizations. We concluded that evoregionalization and phyloregionalization capture distinct evolutionary signals, reflecting the role of in situ diversification vs. phylogenetic turnover resulting from dispersal. Host-parasite co-regionalization is scale-dependent, with increased congruence at regional scales. Despite adult fleas' obligate host dependence, their regionalization is not merely a passive reflection of host biogeography but is also profoundly shaped by environmental conditions. These findings emphasize the importance of method choice, scale and eco-evolutionary interactions in shaping complex biogeographic patterns.

Urogenital schistosomiasis has 2 gender-specific manifestations, male genital schistosomiasis (MGS) and female genital schistosomiasis (FGS). The burdens of MGS and FGS are multifaceted, encompassing financial hardship, emotional and mental health problems and sometimes social stigmatization. Given the pernicious nature of sequelae in the genitalia, managing these chronic health conditions is expensive, difficult and problematic in resource poor settings. Key challenges include lack of epidemiological data on the burden of MGS and FGS, inadequate knowledge among primary and auxiliary health care workers, leading to misdiagnosis, incorrect treatment administration, e.g. overuse of antibiotics, and a lack of appropriate point-of-care diagnostic equipment. Prevention of MGS and FGS is therefore more preferable, however, current preventive programmes and chemotherapy campaigns offering praziquantel are becoming more resource constrained and in most endemic areas are not reaching at-risk adults (and adolescents), sufficiently. Furthermore, there are limited prospects for adequate access to treatment in pre-school children where infections can be first acquired. Therefore, we propose 3 key recommendations guiding movement towards elimination of schistosomiasis as a public health problem: scaling-up praziquantel treatment for other at-risk groups; developing a targeted One Health approach to reduce environmental transmission in both humans and animals; Multi-stakeholder collaboration and community engagement for effective implementation of Water Sanitation and Hygiene components of disease control. Whilst maintaining a school-based approach is still foundational, targeted and sustainable expansion of preventive chemotherapy to other at-risk groups within communities is needed to secure real prospects in elimination of genital schistosomiasis as a public health problem in Africa.

The Liolopidae (Diplostomoidea) are a small family of digeneans that parasitize reptiles and amphibians as adults. Knowledge of intermediate hosts in this family remains scarce, leaving a major gap in the understanding of liolopid biology. To date, the only fully elucidated life cycle is that of Liolope copulans Cohn 1902, a species infecting Asian salamanders, with no other cercarial or metacercarial stages known. This study aimed to identify potential intermediate hosts for Paraharmotrema karinganiense, found in several chelonian species from southeastern Mozambique and South Africa. African apple snails of the genus Lanistes and Nothobranchius killifish were sampled from temporary pools in Karingani Game Reserve, southern Mozambique. Snails were screened over 9 months for cercarial shedding, and encapsulated metacercariae recovered from the spotted killifish (N. orthonotus, Peters) (Cyprinodontiformes: Nothobranchiidae) were excysted for morphological and molecular analyses. Fork-tailed cercariae from Lanistes sp. and 1 metacercaria found in the spotted killifish were genetically identical to the adult of P. karinganiense. This study provides the second documented life cycle of a liolopid trematode and presents the first life cycle for the family based on natural infections, being the first completely documented life cycle for freshwater trematodes from southern Africa. This linkage of larval and adult specimens signifies the importance of Nothobranchius killifish as intermediate hosts as well providing insight in parasite transmission dynamics within temporary aquatic ecosystems.