Parasitology Research最新文献

Studies on avian haemosporidians in Mexico and around the world reveal poor knowledge about the vectors that transmit avian haemosporidian parasites and their association with vertebrate hosts. Seasonal variations given by changes in temperature and precipitation have significant repercussions on the dynamics of vector-borne infections. The seasonal dynamics of major haemosporidian parasites and their main vectors are mostly unknown. This study aimed to determine the presence of avian haemosporidians in hematophagous mosquitoes and to characterize mosquito-vertebrate host interactions during a year in a peri-urban cloud forest in Xalapa City, Veracruz, Mexico. We analyzed 12 species and a total of 1170 hematophagous mosquitoes. We found the presence of Plasmodium and Haemoproteus genera in the blood meals of mosquitoes. The highest haemosporidian detection and mosquito richness were in June (dry-warm season), whereas the highest mosquito abundance was in October (humid-warm season). We recorded three new haemosporidian lineages in this study. Analysis of blood meals showed that mosquitoes fed on different vertebrate groups (amphibians, reptiles, birds, and humans). This study contributed to the knowledge about the distribution of hematophagous mosquito-haemosporidian-vertebrate host interactions.

Toxoplasma gondii and Neospora caninum infect a wide range of domestic and wild animals, including humans, in the case of T. gondii, and cause economic losses in livestock due to abortion and neonatal mortality. In Somalia, zoonotic diseases are concerning due to cultural practices and livestock's economic importance, but surveillance is limited. This study aimed to determine the seroprevalence and molecular prevalence of T. gondii and N. caninum in Somali sheep, goats, and cattle. A cross-sectional study was conducted between December 2018 and January 2020 in Benadir and Lower Shabelle regions of Somalia. Blood samples were collected from 128 cattle, 184 goats, and 46 sheep. Serum samples were tested for anti-T. gondii and anti-N. caninum antibodies using IFAT, and PCR was performed on extracted DNA to detect T. gondii and N. caninum DNA. Overall, 106/358 (29.6%) animals tested positive for anti-T. gondii antibodies, with the highest prevalence in sheep (62.5%), followed by goats (30.4%) and cattle (15.6%) (P < 0.001). For anti-N. caninum antibodies, 13/358 (3.6%) animals tested positive, with cattle showing the highest prevalence (6.2%), followed by goats and sheep (both 2.2%). Co-seropositivity for both antibodies was found in cattle and sheep. Molecular detection of T. gondii DNA revealed a prevalence of 9/358 (2.5%), primarily in sheep (15.2%) and cattle at 1.6% while all goat samples tested negative. No samples were positive for the N. caninum Nc5 gene. This study reveals T. gondii and N. caninum prevalence in Somali ruminants, highlighting the need for better surveillance and control.

Fish are exposed to various parasites such as monogeneans which are flatworms that preferentially affect the gills and skin of these hosts. This study represents the first investigation concerning the distribution of monogenean infracommunities of Enteromius guirali in Cameroon. A total of 100 fish were collected from Cesala River and preserved in 8% formalin solution. Parasite community consisted of Dactylogyrus mendehei and D. nyongensis. These monogenean species adopted an aggregated distribution. Their mean intensities and prevalence increased with host size. Both sides of E. guirali were similarly infested, and no preference for gill arches was recorded for each parasite species. Posterior hemibranch was always the most parasitized, showing the highest parasitic load. Median sector and distal filamentous zone were highly colonized by both monogenean species. This study contributes to understand that the large gill surface offered by great hosts, heterogeneity, bilateral symmetrically of the host's gill system on one hand, and the morphology of haptoral parts and reproduction of parasites, on the other hand, are the main factors which determine the distribution of studied component community.

Canine visceral leishmaniasis (CVL) is a parasitic disease caused by the protozoan Leishmania infantum. Neurological infection occurs due to the parasite's ability to cross the blood-brain barrier. It is known that dogs can remain infected with a subclinical infection for life, potentially acting as reservoirs for L. infantum when bitten by sandflies. In this context, the objective of this study was to evaluate the occurrence of Leishmania spp. in the brains of dogs from the metropolitan region of Rio Grande do Sul, Brazil, without a history of neurological disease but residing in an endemic area for L. infantum. A total of 200 samples, from 2022 to 2023, were evaluated using conventional Polymerase Chain Reaction (PCR) with the primers Leishmini-F GGKAGGGGCGTTCTGC and Leishmini-R STATWTTACACCAACCCC, aiming to amplify a product of 120 base pairs for Leishmania spp. To identify the species, a multiplex PCR was used, differentiating L. braziliensis (127 bp), L. amazonensis (100 bp), and L. infantum (60 bp), with the molecular target being the conserved region of the kinetoplast DNA (kDNA) minicircle, specific to Leishmania spp. Of the 200 samples evaluated, 26.5% (53/200) tested positive in the conventional PCR reaction for Leishmania spp., with the PCR multiplex the only species detected was Leishmania infantum. The average age of the positive animals was 5.08 years, with 47.2% being females and 52.8% being males; among these, mixed-breed dogs were the most predominant, representing 43.4% of the total. Clinical signs varied: hepatomegaly in two dogs, pronounced neutrophilic hepatitis in one, splenomegaly in one with lymphoid hyperplasia, and glomerulonephritis and nephritis in two animals. Mild anemia and thrombocytopenia were found in eight, with pale mucous membranes in three, and diffuse alveolar edema in one case. Notable pathological findings included suspected distemper in one animal and lymphoplasmacytic meningitis in another. Histopathological findings revealed alveolar edema and acute renal failure. A third dog exhibited bilateral hydrocephalus and diffuse edema in the brain. Additional changes, such as mild inflammatory infiltrate and slight vacuolar degeneration, were observed in 11.3% of the analyzed brains. There was no clinical suspicion of leishmaniasis in any of the studied cases. Therefore, the detection of L. infantum DNA in the brains of dogs suggests that animals with subclinical infection may play a crucial role in the spread of leishmaniasis, and infection by Leishmania spp. should be considered as a differential diagnosis for neurological disease in endemic areas for the protozoan.

Cryptosporidium is a waterborne pathogen that causes diarrhea in vertebrates and humans (mainly C. hominis and C. parvum). Ozone (O₃) is a powerful disinfectant due to its high oxidative characteristics, and it is used to inactivate microorganisms in drinking water. As an alternative to the gas dissolution system for producing ozone from oxygen, a simpler electrolytic ozone generation system has recently been developed. In the present study, the efficacy of the ozonated water produced by this system in inactivating Cryptosporidium parasites (C. parvum) was evaluated at different current intensities (which change the ozone concentrations) and short exposure times (15-60 s). Oocyst viability and integrity was assessed using vital dye staining, excystation assays, and scanning electron microscopy (SEM). SEM data revealed that oocyst walls were damaged by exposure to ozone molecules even at low concentrations (< 0.01 mg/l for 1 min) (current intensity 0.2 A), but that the excystation assay could not differentiate between deformed oocysts (dead) and partially excysted oocysts (alive). Exposure to ozonated water produced with a low current intensity (0.3 A) for 15 and 120 s resulted in the inactivation of 96.2% (CT value < 0.003) and 99.4% (CT value < 0.020) of the oocysts, respectively. Thus, it was estimated that a CT value more than 0.020 was required to inactivate > 99% of the C. parvum oocysts. These results suggested that the electrolytic ozone generation system may be more effective than gas dissolution ozone generation; however, further studies using additional approaches are needed to obtain clearer evidence.

In Brazil, the wild boar (Sus scrofa) is the main invasive exotic species, responsible for causing various economic, environmental, and health damages to biodiversity. In view of the above, we aimed in our study to investigate the occurrence of endo and ectoparasites in free-ranging wild boars in the northwest region of the state of São Paulo, Brazil. In total, 45 animals of different sexes and ages were examined in this research. Fecal and urine samples were processed using coproparasitological techniques. Multiple incisions in muscles, liver, and pancreas were also made to investigate cestodes and trematodes, and the entire epidermal region of the animals was analyzed for ectoparasites search. In our study, we demonstrate an occurrence of 97.77% (44/45) and 43.33% (13/30) of endo and ectoparasites, respectively, in wild boars, with the identification of eggs of Metastrongylus spp., Strongyloides ransomi, Trichuris suis, Stephanurus dentatus, and nematodes of the order Strongylida, as well as oocysts of Eimeriidae protozoa. Ectoparasite infestations were mainly caused by ixodids of the genus Amblyomma spp. and by larvae of Cochliomyia hominivorax.