Parasitology Research最新文献

Fasciolosis, a neglected tropical disease caused by Fasciola spp., is a global parasitic infection whose prevalence is on the rise, particularly in warmer regions with favorable temperature and humidity conditions. This study examines the temporal presence of Fasciola spp. in various climatic zones across Iran, focusing on Gilan province as an endemic area. We calculated the Malone index for 5-year intervals spanning significant epidemics in 1988 and 1999 in Gilan, as well as 2005, 2010, 2015, and 2020. The results revealed a significant increase in Malone indices during August, September, and October in 1988, indicating a higher risk for Fasciola presence than in other months. These months were categorized as moderate risk. In 1999, September exhibited moderate risk, while October was classified as low risk. The risk levels remained relatively low in 2005, with the highest value in September and October. Similarly, October and September showed the highest risks in 2010, while October was identified as highly risky in 2015. In 2020, August displayed a higher risk, while September, October, and November indicated low risk. The analysis highlights the variability of risk levels across different years, with September and October consistently appearing as months with a higher probability of Fasciola presence. Conversely, the risk diminishes from January to July, which is considered a low-risk period in the region. Interestingly, a comparison with three different geographical regions in central, southern, and western Iran revealed that the Malone index was zero in all months of the year, except for two cases, suggesting unfavorable conditions for Fasciola presence in these areas. This research sheds light on the complex interplay between climatic variables and the presence of Fasciola spp., with the potential to inform the development of targeted strategies for preventing and controlling this parasite in Gilan province, a known hotspot for fasciolosis, as well as in other regions with similar climatic conditions.

Chagas disease, caused by Trypanosoma cruzi, remains a significant public health problem in Mexico, particularly challenging to diagnose during its chronic phase, due to low parasitemia and the complex immune response. According to the Pan American Health Organization, no single test is sufficiently sensitive or specific to reliably detect chronic Chagas disease, requiring the use of multiple serological methods when results are inconclusive. This study aimed to assess the seroprevalence of Chagas disease in the largely uncharted municipalities of the North of State of Mexico. A total of 250 serum samples from 17 municipalities were analyzed using a comprehensive approach involving three serological tests: the BIO-CHAGAS commercial kit (MEXLAB®), an ELISA test with antigens derived from an endemic strain, and a confirmatory Western blot analysis. The results revealed that 240 samples were negative, 3 were inconclusive, and 7 were positive, yielding a seroprevalence rate of 2.8% (7/250). The endemicity demonstrated in the municipalities of Hueypoxtla and Tequixquiac, combined with the documented presence of the vector Triatoma barberi in these areas, suggests an ongoing risk of T. cruzi transmission. These findings underscore the urgent need for targeted public health interventions, including increased surveillance, community awareness, vector control programs, screening tests to identify cases, and prompt treatment, to curb the spread of Chagas disease in this region.

Trichomonas vaginalis infections significantly impact public health and are associated with increased likelihood of HIV infection, prostate cancer, and pregnancy complications. Current treatment relies almost exclusively on 5-nitroimidazoles, particularly metronidazole, raising concerns about drug resistance and treatment efficacy. This study is aimed at evaluating the effectiveness of metronidazole and tinidazole on metronidazole-resistant strains of T. vaginalis and at determining whether efflux pump inhibitors could reverse metronidazole resistance. Additionally, the roles of nitroreductases in metronidazole resistance were also studied. Metronidazole and tinidazole were tested on both metronidazole-sensitive and -resistant T. vaginalis strains. A checkerboard assay was conducted to assess the potential synergy between metronidazole or tinidazole and efflux pump inhibitors. Nitroreductase activity and ferric iron reduction assays were employed to study the functions of nitroreductases. Tinidazole demonstrated better effectiveness against metronidazole-resistant strains compared to metronidazole, with lower minimal lethal concentration levels. However, the tested efflux pump inhibitors did not significantly enhance the efficacy of metronidazole or tinidazole. Pyrimethamine showed some activity but did not improve the efficacy of the 5-nitroimidazoles in combination. Investigations into the role of nitroreductases and other enzymes in metronidazole resistance revealed no clear downregulation trend in resistant strains. Notably, nitroreductase 8 was capable of reducing ferric iron. While tinidazole remains a viable alternative for treating metronidazole-resistant T. vaginalis, efflux pump inhibitors do not effectively reverse resistance. The identification of nitroreductase's 8 iron-reducing activity suggests its involvement in metronidazole resistance mechanisms. This finding highlights the need for continued research to develop new treatment strategies and improve the management of trichomoniasis, ultimately reducing its public health burden.

Nippostrongylus brasiliensis is an intestinal parasite of rodents with a worldwide distribution. Due to the similarities between its life cycle and that of the human hookworms Ancylostoma duodenale and Necator americanus, N. brasiliensis has been widely used as a model in experimental research. We provide new data on the embryonation and hatching processes of N. brasiliensis eggs, not in the soil, but in the large intestine of naturally infected Rattus norvegicus. The parasite was investigated in 109 rats trapped in urban and periurban areas of Valencia, Spain. Rats were preserved at - 20 °C. After thawing, all the rat organs were examined. The contents of the large intestine were analysed by the Midi-Parasep® technique. N. brasiliensis (adult prevalence 69.72%) was identified by morphological and molecular techniques. Parasite eggs were found in 88.16% of the sediments. In addition to unembryonated eggs, eggs in different stages of embryonation were encountered in 67 of the 76 contents (88.16%). Free larval stages (L1 and more developed larvae) were also found in 47 of the 76 (61.84%) sediments studied. Filariform larval stages of N. brasiliensis were also sporadically detected in the lungs of the infected rats. According to our results, the development of eggs and larvae in the intestine of naturally infected rats opens up the possibility of autoinfection in the natural life cycle of N. brasiliensis, which could explain the high burdens of adult stages frequently found in the small intestine of infected rats.

To improve our knowledge on host-parasite interaction, the study was undertaken on Rhipicephalus microplus infestation in cross breed cattle. This tick, being a voracious blood sucker, remains attached to the skin for prolonged period and inoculates saliva during blood feeding. Biomolecules present in the saliva have detrimental effects on host system. The present study deals with the effects of R. microplus in artificially infected nine months old cattle for a period of 21 days. There was physiological alteration during tick infestation in terms of body temperature, pulse, and respiration rate. There was drop in haemoglobin gram percentage, platelet count, total red and white blood cell count. Thrombocytopenia in infested animals was suggestive of iron deficient anaemia after artificial infestation. R. microplus infestation was found to induce stress in experimental animals. Our study on peripheral blood gene expression was suggestive of Th2 polarization since there was increased IL-4 response. Increased IL-6 response indicated skin damage due to R. microplus infestation and we further correlate eosinophilia with up-regulation of IL-6 and IL-8 responses. Increased IL-10 response and decreased IFN-γ response were suggestive of immunosuppressive and anti-inflammatory properties of tick saliva.

The order Piroplasmida (e.g., Babesia, Theileria, Cytauxzoon, and Rangelia) and suborder Adelorina (e.g., Hepatozoon) comprise protozoa of the phylum Apicomplexa, which are related to significant economic, veterinary, and medical concerns. This study aimed to investigate the molecular occurrence and evaluate the phylogenetic placement of the Hepatozoon and Piroplasmida agents in small mammals (rodents and marsupials) in midwestern Brazil. The maximum likelihood phylogenetic inference positioned the 18S ribosomal RNA (18S rRNA) sequences of Hepatozoon obtained from Hylaeamys megacephalus with those previously detected in Didelphis aurita from Brazil; however, the sequences of Hepatozoon retrieved from Nectomys rattus and Neacomys amoenus clustered in a sub-clade sister to a clade of sequences detected in small rodents from Brazil. Phylogenetic inference positioned the piroplasmid 18S rRNA sequences detected in Thrichomys pachyurus in a single sub-clade sister to a clade containing sequences previously detected in the Phyllostomidae bat Phyllostomus discolor from midwestern Brazil. In contrast, the piroplasmid cytochrome b mitochondrial gene (cytB) sequences obtained from T. pachyurus clustered into a single clade. In conclusion, a new host record is provided for Hepatozoon spp. from the rodent N. amoenus. Furthermore, this study expanded the Piroplasmida order diversity by identifying novel genotypes in T. pachyurus rodents, which were genetically related to the piroplasmid clade found in Neotropical bats and named herein the "South American Rodentia group."

Specific information about the dispersion of Culex quinquefasciatus from Dschang in western Cameroon is scarce, and evidence-based interventions are needed. Common use of larvicides and adulticides conduct to the development of vectors resistance which can lead to deep biological changes, including fitness costs. We assessed the profile of insecticide resistance in field populations of Cx. quiquefasciatus and its potential fitness cost in a lineage selected for deltamethrin and permethrin resistance in the laboratory for two generations. The resistance intensity of the Cx. quinquefasciatus population was moderated when the population was exposed to deltamethrin at 10 × . Preexposure to PBO led to the restoration of full susceptibility to both deltamethrin and permethrin. Compared with that of the control group, female fecundity rates, egg hatchability, and pupation rates were significantly lower in the insecticide exposed groups. Larval development time and adults emergence rates were comparable between insecticide-exposed groups and the control. Insecticide-exposed adults lived longer than control adults did. Our findings suggest that the mechanisms selected for pyrethroid resistance are associated with negative impacts on different life-trait parameters and support the hypothesis that insecticide resistance is related to a high fitness cost.

Digeneans of the family Notocotylidae differ from other digeneans in their peculiar eggs. The eggs feature a pair of long filaments extending from their poles, and their contents differ significantly from what we expect to observe in the eggs of digeneans. Instead of a ciliated miracidium larva, the notocotylid egg contains a tiny few-celled mother sporocyst. This sporocyst infects a snail host following accidental ingestion of the egg. Previous transmission electron microscope studies elucidated the structure of the sporocyst and proposed a mechanism of the injection relying on the structure called the opercular cord, but the data were insufficient to describe certain details. Here, we present ultrastructural data on the egg of Paramonostomum, clarifying the nature of the injection apparatus and providing the missing details of the in-egg mother sporocyst structure. We found the opercular cord to be part of the eggshell associated with the vitelline membrane. We also elucidated the intertwining connection between the germ cells and the sporocyst's tegument and explored 'nuage' granules present in the cytoplasm of the germ cells, providing evidence for identification of these cells as the germ ones. We discuss our findings in the context of transition of miracidia to a passive strategy of snail infection.

Biting midges of genus Leptoconops Skuse 1889 are small blood-feeding insects recognized as highly irritating diurnal pests in certain regions around the globe. In Europe, their presence is poorly documented, except in France and Italy. Following reports of human discomfort in a tourist area of Menorca, Balearic Islands (Spain), a small-scale study was conducted to identify the biting species and assess their preferred biting sites using a human-landing assay along a habitat gradient in a coastal dune area. Leptoconops irritans (Noé, 1905) was identified based on morphological features and DNA barcoding. This species reached high densities (average rates of 3.3 landings/min), particularly near coastal dune vegetation. No statistically significant differences were found among the four main body sites for landings of L. irritans (F_3,6.023 = 1.80, p = 0.250): head (n = 91, 53.8%), lower extremities (n = 39, 23.1%), upper extremities (n = 37, 21.9%), and other covered areas (n = 2, 1.2%). Landing preferences varied among the three volunteers, and bites progressed differently. This study represents the second documented case of Leptoconops midges causing human discomfort in Spain. We hope this research will stimulate further interest in this understudied genus, which has been largely overlooked across much of Europe.

Canine leishmaniosis (CanL), caused by Leishmania infantum, is a widespread vector-borne disease. In Italy, an endemic region for CanL, overlapping transmission of L. infantum and tick-borne pathogens (TBPs) like Anaplasma phagocytophilum and Ehrlichia canis is increasingly reported. Dogs with clinical leishmaniosis often show higher co-infection rates and pronounced clinicopathological abnormalities. This study presents a systematic literature review and new findings from southern Italy, focusing on co-infections with E. canis and A. phagocytophilum in clinically healthy L. infantum seropositive and seronegative dogs. The systematic review identified two eligible studies. The first reported 34/488 (7%) dogs L. infantum seropositive, with 11.8% also seropositive for A. phagocytophilum. Among 454 seronegative dogs, 3% were seropositive for A. phagocytophilum and 2.4% for E. canis. The second study identified 154/1260 (12.2%) dogs L. infantum seropositive, with co-infection rates of 0.6% and 1.9% for A. phagocytophilum and E. canis, respectively. Among 1106 seronegative dogs, 1.3% were seropositive for A. phagocytophilum and 2.3% for E. canis. In the retrospective study from southern Italy, 90/154 (58.4%) dogs were L. infantum seropositive, with co-infection rates of 4.4% for A. phagocytophilum and 2.2% for A. phagocytophilum and E. canis. Among 64 seronegative dogs, 1.6% showed similar co-infections. This is the first systematic review in Italy, documenting low and comparable co-infection rates with A. phagocytophilum and E. canis in clinically healthy dogs, regardless of L. infantum serostatus. These findings suggest that co-infections may occur independently, offering insights into vector-borne disease dynamics in endemic areas.