Parasitologia

Helminth parasites secrete several types of biomolecules to ensure their entry into and survival in their hosts. The proteins secreted to the extracellular environment participate in the pathogenesis and anthelmintic immune responses. The aim of this work was to identify and functionally annotate the excretory/secretory (ES) proteins of the monogenean ectoparasite Rhabdosynochus viridisi through bioinformatic approaches. A total of 1655 putative ES proteins were identified, 513 (31%) were annotated in the UniProtKB/Swiss-Prot database, and 269 (16%) were mapped to 212 known protein domains and 710 GO terms. We identified six putative multifunctional proteins. A total of 556 ES proteins were mapped to 179 KEGG pathways and 136 KO. ECPred predicted 223 enzymes (13.5%) and 1315 non-enzyme proteins (79.5%) from the secretome of R. viridisi. A total of 1045 (63%) proteins were predicted as antigen with a threshold 0.5. We also identified six venom allergen-like proteins. Our results suggest that ES proteins from R. viridisi are involved in immune evasion strategies and some may contribute to immunogenicity. Full article

The Iberian Peninsula is one of the most humanized areas in Europe, yet humans may cohabit with large predators, such as the Iberian wolf (Canis lupus signatus), at the expense of many contributions to its conservation. The limited wolves’ territory leads to a close relationship between this wild species, humans, and other animals, which may promote the spillover of pathogens, such as gastrointestinal parasites. This review intends to provide an update concerning gastrointestinal parasite findings performed using coprological methods on fecal samples from Iberian wolves. Studies conducted in Portugal and Spain through coprology presented a prevalence of gastrointestinal parasites of 57.0–100% in Spain and 21.5–68.3% in Portugal. Parasites belonging to Protozoa, Trematoda, Cestoda, and Nematoda were specified, alongside thirteen genera and twenty species of gastrointestinal parasites. In this study, 76.9% (10/13) of genera and 65.0% (13/20) of species of gastrointestinal parasites were identified as having zoonotic potential. These results highlight that further studies are needed to better understand the parasitic agents circulating in the wild in humanized areas, such as the Iberian Peninsula. Full article

Infectious parasites, especially the intestinal protozoan parasites, continue to be a major public health problem in Africa, where many of the same factors contribute to the transmission of these parasites. This study was conducted to investigate the parasites causing intestinal protozoal infections diagnosed in Aristide Le Dantec hospital (Senegal). Direct examination and the Ritchie technique were used. Among the 3407 stool samples studied, 645 demonstrated the presence of intestinal protozoa in single parasitism, biparasitism, or polyparasitism, representing a prevalence of 18.93%. Out of a total of 645 protozoa, 579 (16.99%) were identified in monoparasitism in the following order: Entamoeba coli (6.87%) and Blastocystis hominis (5.69%) for low pathogenic species, and Entamoeba histolytica/dispar (2.31%) and Giardia intestinalis (1.32%) for pathogenic species. The rates of biparasitism and polyparasitism were 1.88% and 0.06%, respectively. The highest rate of parasites was 24.83% between the ages of 0–15 years. A logistical regression model indicated that intestinal protozoan infections were not associated with age groups. There was an association between age groups and Giardia intestinalis and Blastocystis hominis (p < 0.05). These results demonstrated the frequency of intestinal protozoa in Senegal. There is a need to implement treatment, prevention, and control measures to limit the circulation of these protozoan infections. Full article

Acute Chagas disease (ACD) caused by Trypanosoma cruzi has emerged as a major food-borne disease in Brazilian Amazonia. For the first time, we characterized an outbreak of orally acquired ACD in Acre, in the forest community of Seringal Miraflores, affecting 13 individuals who shared the pulp of açai palm berries: 11 adults and two children (one newborn), all diagnosed by thick-drop blood smears. The fluorescent fragment length barcoding method, which simultaneously identifies species/genotypes of trypanosomes in blood samples, uncovered an unprecedented genetic diversity in patients from a single outbreak of ACD: T. cruzi TcI in all patients, mostly concomitantly with the non-pathogenic Trypanosoma rangeli of genotypes TrA or TrB, and TcI, TcIV, and TrB in the child. The patients presented persistent fever, asthenia, myalgia, edema of the face and lower limbs, hepatosplenomegaly and, rarely, cardiac arrhythmia. The clinical symptoms were not correlated to gender, age, or to trypanosome species and genotypes. The inferred SSU rRNA phylogenetic analyses of trypanosomes from humans, triatomines and sylvatic hosts included the first sequences of T. cruzi and T. rangeli from humans in southwestern (Acre and Rondônia) Amazonia, and the first TcI/TcIV sequences from Rhodnius spp. from Acre. The sylvatic transmission cycles of genetically different trypanosomes in landscapes changed by deforestation for human settlements and increasing açai production is a novel scenario favoring trypanosome transmission to humans in Acre. Full article

Full-length cDNAs encoding macrophage inhibitory factor-2 (MIF-2) were cloned from Teladorsagia circumcincta (TcMIF-2) and Haemonchus contortus (HcMIF-2). TcMIF-2 and HcMIF-2 cDNA (342 bp) encoded proteins of 114 amino acids, each of which was present as a single band of about 16 kDa on SDS-PAGE. Multiple alignments of the protein sequences showed homology of 84% between TcMIF-2 and HcMIF-2, 54–76% with MIF-2s of seven nematodes, but low homology with other MIF sequences. The predicted three-dimensional structures revealed an overall structural homology of TcMIF-2 and HcMIF-2, highly conserved binding and catalytic sites and minor differences in the tautomerase binding site residues in other nematode MIF-2 homologues. A phylogenetic tree was constructed using helminth and mammalian MIF-1 and MIF-2 sequences. Soluble C-terminal MIF-2 proteins were cloned in arabinose inducible promotor AY2.4, expressed in Escherichia coli strain AY2.4 and purified. Recombinant TcMIF-2 and HcMIF-2 had similar enzyme activities in a standard tautomerase assay. Recombinant HcMIF-2 activity was approximately halved by storage at 4 °C, −20 °C or −70 °C. Antibodies in serum and saliva from field-immune, but not nematode-naïve, sheep recognised recombinant HcMIF-2 and TcMIF-2 in enzyme-linked immunosorbent assays. Recognition of the recombinant proteins by antibodies generated by exposure of sheep to the native enzyme indicates similar antigenicity of the two proteins. Full article

Cystic echinococcosis (CE) is endemic in Argentina, and approximately 30% of the national territory has characteristics appropriate for the development of the zoonotic domestic cycle of this disease. This community-wide study was implemented in rural areas of Añatuya, Santiago del Estero (northern Argentina) to determine the presence of Echinococcus granulosus sensu lato in the definitive host (dogs) and the presence of CE in humans. Infection data from dogs were obtained through the collection and analysis of fecal samples; these were processed through sedimentation/flotation techniques and PCR. The presence in humans was determined by ultrasound (US) and serology (ELISA confirmed by Western Blot—WB) in the Miel de Palo settlement. A standardized questionnaire was used to investigate potential risk factors for CE; more than half of the studied population carried out activities that favor the maintenance of the cycle. The prevalence of E. granulosus s.l. in dogs from 10 rural settlements, confirmed by PCR, was 4.7% (32/678). The results of the US and serology screening showed a human prevalence of 0.55% (1/183) in Miel de Palo. This prevalence increased to 4.9% (9/183) if imaging-negative but serology-positive (ELISA+WB) individuals are included, as per national guidelines. One of the participants with CE, confirmed by US, was less than 15 years old, which evidences the presence of active transmission. A comprehensive multidisciplinary approach, taking into consideration social, behavioral, sanitary, and environmental aspects intimately tied to the parasite cycle, is needed. Full article

Hematophagous leeches express a broad variety of secretory factors in their salivary glands; among them are hirudins, inhibitors of blood coagulation, and decorsins/ornatins, inhibitors of platelet aggregation. Here, we describe the identification and molecular and functional characterization of putative hirudins and decorsins/ornatins in two leech species of American origin, Limnobdella mexicana and Haementeria vizottoi. The leech species represent two orders of leeches, the proboscis-bearing Rhynchobdellida and the non-proboscis-bearing Arhynchobdellida. Members of the hirudin superfamily, such as hirudins or decorsins/ornatins, are described for the first time in the genus Haementeria. Both species expressed very potent inhibitors of platelet aggregation, but only the putative hirudins of L. mexicana displayed high thrombin-inhibitory potency, whereas the putative hirudin of H. vizottoi turned out to be a hirudin-like factor. The results of our study provide new insights into the evolutionary background of the blood-sucking lifestyle in leeches. Full article

Japanese encephalitis virus (JEV) is a mosquito-borne virus primarily found in Asia and Australia and is one of the few with an associated human/animal vaccine. Swine are amplifying hosts and wading birds are reservoirs of JEV, while horses and humans are incidental hosts. The primary vector is Culex tritaeniorhynchus, a generalist blood feeder not found in the United States (US); secondary vectors (e.g., Cx. pipiens, Cx. quinquefasciatus, Aedes japonicus, Ae. vexans) are widespread in the US (including North Carolina [NC]). The risk of JEV to NC was investigated because of widespread swine production, human populations, bird hosts, and possible mosquito vectors; however, recommendations can also apply to other swine producing states and regions. A brief review was conducted to identify transmission competent arthropod vectors, vertebrate hosts, and vector-host interactions for JEV. NC and other areas may be at risk for JEV emergence because of factors such as active international trade, volume of swine production, permissive climate, and widespread occurrence of potential vector species. Improved knowledge of the spatial distribution of swine farms, tracking movement of live swine, assessment of vector competence/capacity and blood feeding habits of potential JEV vectors, investigation of a JEV sentinel surveillance system, and assessment of efficacy for current biosecurity and control measures is needed to protect public and veterinary health. Full article

Introduction: Blastocystis sp. is a unicellular obligate anaerobic protozoa found in the human intestinal tract. Its role in human health is widely discussed because of the high proportion of asymptomatic carriers. In sub-Saharan Africa, the prevalence of the disease is underestimated. This study was performed to describe the epidemiological, clinical, and parasitological aspects of Blastocystis sp. infection in patients attending to Fann University Hospital. Material and Methods: We carried out a retrospective and descriptive study among patients attending to the laboratory of Parasitology and Mycology of Fann University Hospital from January 2016 to December 2020. All stool samples collected were examined using direct examination, a formal ether concentration method, and a modified Zeilh–Nielsen staining method. A descriptive analysis was performed with Stata MP 16 software. The significance level was set at 5%. Results: Overall, 447 cases of Blastocystis sp. were reported in our study, representing a prevalence rate of 13.7% ((447/3264) (95% CI: 12.5–15.5)). The mean age of the patients was 26 ± 20.7 years. Subjects over 45 years of age were more affected, with a frequency of 14.7%. Blastocystis sp. carriage was more common in males, at 14.6%. The symptomatology was mainly represented by diarrhea, abdominal pain, and dyspeptic disorders. In asymptomatic patients, the frequency of Blastocystis sp. was 33.3%. Mono-infection was found in 78.6% of cases. In total, 96 patients were carriers of at least two parasites (21.5%). Blastocystis sp. was most associated with Entamoeba coli (8.1%) and Endolimax nanus (4.03%). The association with helminths was noted in 5 patients (3 Ascaris lumbricoides, Trichuris trichiura, and Taenia). Conclusion: These results show the frequency of Blastocystis sp. infection with a large proportion of asymptomatic carriers. The presence of the parasite in the stool, associated with digestive disorders or with the association of other intestinal parasites, could justify the initiation of an anti-parasitic treatment. Full article

The rapid growth in the human population has led to an increased requirement for readily available food sources. The aquaculture industry is a fundamental source for maintaining food supplies; however, it is subjected to mounting pressures to meet supply demands. Thus, limiting factors that negatively impact the cultivation of farmed aquatic organisms is essential. Gill disease is an increasing area of concern, resulting in substantial losses in farmed fish. Several microbial pathogens are known to cause gill disease and, in many instances, multiple pathogens or factors can be involved in the disease, resulting in complex gill disease (CGD). The role of mixed infections in gill disease is largely unknown, as such this review aims to examine data on previous infections and highlight the variety of microbes that might be involved in gill disease. The influence of climate change in the context of CGD is also discussed given the strong links between physicochemical extremes and numerous microbial gill pathogens. Understanding these factors will allow for improved diagnostic and therapeutic strategies to be implemented. Full article

Populations of Triatomas infestans with different susceptibility to pyrethroid insecticides were reported to have distinct evolutionary and epidemiological characteristics. We aimed at evaluating metacyclogenesis and parasite load as measures of vector competence and feeding/defecation patterns as vectorial capacity estimates of a group of resistant (“R”) and susceptible (“S”) T. infestans. Third instar nymphs of each group were fed on mice infected with Trypanosoma cruzi (Tulahuén strain, DTU VI). Parasite concentration in blood was quantified by real-time PCR (qPCR) for each mouse. The time at which feeding started, the span of feeding, the volume of blood consumed, and the time taken to defecate were measured. At 30 days post-feeding, feces were analyzed in parallel by optical microscopy (percentage of metacyclic trypomastigotes, % MT), and qPCR (total T. cruzi DNA). The ratio of parasites consumed/defecated by nymphs of each group was used to estimate the parasites’ survival and multiplication inside the triatomines’ gut. It was estimated that for each blood trypomastigote consumed, 6.6 parasites were obtained in the feces of “R” nymphs, and 7.9 in “S”. “R” nymphs consumed a higher volume of blood, had lower % MT in their feces (lower vectorial competence), and took longer to defecate (lower vectorial capacity) than “S”. Full article

An adult engorged female of the hard tick Amblyomma ovale was found during a routine examination of a bloodhound dog in a private clinic from a small community in the state of Oaxaca, in Southern Mexico. Previously, this tick species had been identified in dogs from four states in the country, where it has been involved as a carrier of Rickettsia spp. To our knowledge, this is the first time that A. ovale has been detected in Oaxaca. Public and animal health authorities should be aware of this and other tick species that may be acting as vectors of tick-borne pathogens (TBP) to both humans and animals. Full article

Coenurosis due to Taenia multiceps has emerged as a major concern to small ruminant-owning communities in northern Tanzania. Although a high incidence of disease has been reported, gaps still remain in our knowledge of the disease problem across different agro-ecological settings. The study aimed to determine the prevalence of coenurosis in small ruminants and taeniid infection in dogs and identify risk factors for infection. Questionnaire surveys, postmortem examination of small ruminants, and coproscopic examination of dog faeces were used to collect data on reported coenurosis cases and taeniid infections, respectively. The twelve-month period prevalence of coenurosis in small ruminants was 8.4% (95% CI 8.2–8.6). The prevalence of taeniid infection in dogs was 12.5% (95% CI 9.1–17.4). The village-level prevalence of coenurosis in sheep and goats was significantly correlated with taeniid infection prevalence in dogs (r = 0.51, p = 0.029). Multivariable analysis indicated that home slaughter was significantly associated with the livestock owner-reported neurological syndrome due to coenurosis in sheep and goats (OR = 13.3, 95% CI 4.2–42.0, p < 0.001) and the practice of offering discarded brains to dogs was significantly associated with taeniid infection prevalence in dogs (OR = 2.80, 95% CI 0.98–7.98, p = 0.05). Coenurosis is a major disease problem in livestock-keeping communities of northern Tanzania, but there is little awareness of transmission risks associated with home slaughter and dog feeding practices. There is a need for veterinary and animal health services to engage more actively with communities to increase awareness of the transmission cycle of T. multiceps and the preventive measures that can be taken to reduce the impact of disease in livestock-dependent communities. Full article

The concern about the protection of wildlife has been gathering attention from researchers worldwide. Zoos and aquariums have become widely recognized sites for the conservation of wildlife. However, the persistence of the illegal trade of wild animals, such as reptiles, and their use as pets can endanger not only the preservation of the species, but also allow the introduction of new pathogens and zoonotic diseases. It is important to highlight that preventive exams should be carried out prior to introducing these animals into a new facility to guarantee zoological management strategies. There are several reports of parasitism in reptiles, some of them with zoonotic potential, such as the genus Cryptosporidium spp. In Brazil, reports that explore the prevalence of cryptosporidiosis in reptiles are scarce, and very few have used molecular methods for the detection of Cryptosporidium spp., or the genotyping of its species and subtypes. This review aims to help professionals in the area and encourage them to increase their attention to this protozoan, which is usually neglected. Full article

This paper discusses a process of developing the data analysis and modeling of Pasteuria penetrans spore attachment in vitro and in planta, based on the observation that the number of spores attaching to juveniles within a given time increased by increasing the time of exposure to spores and the spores dose. Based on this, the P. penetrans spore attachment in vitro was modeled using the negative binomial distribution which permits decomposing the observation’s variability into three components: randomness, internal differences between individuals, and the presence of other external factors, e.g., the soil type. Additionally, we developed case-detection methods to explain P. penetrans spores’ attachment variability. The statistical methods developed in this paper show that a nematodes invasion is significant limited when second stage juveniles (J2s) are encumbered with seven P. penetrans spores. This research study concludes that the number of spores attached in J2s, the time of exposure of J2s to P. penetrans spores, and the soil texture are important factors affecting the invasion of root-knot nematodes in tomato plants. Full article

Toxoplasmosis and chlamydiosis remain among the primary causes of abortion and fetal loss in small ruminants. Consequently, they are a source of considerable economic losses for farmers. The objectives of this study were to determine the seroprevalence and highlight the risk factors associated with Toxoplasma gondii and Chlamydophila abortus infection in small ruminants in Cameroon. A cross-sectional study was conducted in 200 small ruminant farms during a period from April to October 2021. A total of 1061 small ruminants were sampled, and the sera obtained were analyzed using the indirect ruminant multi-species ELISA test for specific IgG antibody detection for T. gondii and C. abortus at the National Veterinary Laboratory. A questionnaire was constructed to collect information about flock management and risk factors possibly associated with T. gondii and C. abortus infection in goats and sheep. Overall, 329 small ruminants tested positive for T. gondii-specific IgG antibodies and 45 for C. abortus-specific IgG antibodies with a seroprevalence of 31.1% (95% CI: 28.2–33.8) for T. gondii and 4.2% (95% CI: 3.0–5.5) for C. abortus, respectively. However, a significant co-infection of 1.8% (95% CI: 0.37–3.3) was obtained between T. gondii and C. abortus (p = 0.02). Linear regression model analysis revealed that, the seroprevalence of T. gondii at the flock level was significantly correlated with the region (0.22 CI: 0.17; 0.26) the breeding objectives (0.36 CI: 0.17; 0.56) the level of hygiene (0.11 CI: 0.01; 0.21) and presence abortions (0.55 CI: 0.46; 0.64) on the farms and that of C. abortus was significantly correlated with the regions (0.01 CI: 0.00–0.02) and degree of abortion on the farms (−0.26 CI: −039; −0.14). At the individual level, a significant correlation was observed between the seroprevalence of T. gondii and region (−0.09 CI: −0.14; −0.04), species (0.07 CI: 0.01–0.14), sex (−0.11 CI: −0.18; −0.03), age (0.08 CI: 0.04–0.12) and physiological status (0.21 CI: 0.18; 0.24). For C. abortus seroprevalence, a significant correlation was observed with the regions (0.02 CI: 0.00; 0.03) and breed (0.01 CI: 0.01; 0.02) of small ruminants reared in the northern regions of Cameroon. These results could be used to implement efficient management measures to prevent and control T. gondii and C. abortus infection in goats and sheep in Cameroon. Full article

Acanthamoeba keratitis (AK) is a potentially blinding infection caused by protozoa found worldwide. The topical application of biguanides and diamidines is the most common anti-amoebic treatment for AK. In this study, we hypothesized that geographical location and socioeconomic status influence the management and treatment of AK. To test this hypothesis, we analyzed case reports and series of Acanthamoeba eye infections from different geographic regions to evaluate the association between diagnosis, treatment, and outcome worldwide. This study looked specifically at case reports of patients with diagnosed AK using bibliographic databases such as PubMed, BioMed Central, and Google Scholar, which were searched between 30 April 1990 and 1 May 2022. The search identified 38 eligible studies that provided data for 60 clinical cases of AK. The results indicated that current standard treatments are effective if the infection is identified early and that delays can lead to clinical symptoms, including permanent visual opacities. There was evidence suggesting an association between the treatment regimen practiced in certain geographic regions and treatment outcome. Patient access to medical facilities and economic background also had an influence on the treatment and outcome of AK. Further analysis of more case reports can expand our understanding of the influence of specific demographic and individual patient characteristics on the effectiveness and accessibility of AK medicines. Additionally, using a living systematic review approach to incorporate emerging evidence will reveal the relative merits of different treatment regimens for AK and outcomes. Full article