Fecal shedding level of Haemonchus contortus is associated with gastrointestinal bacterial microbial composition in naturally infected sheep.

A complex interaction of gastrointestinal parasites with sheep hosts may involve bacteria communities, parasite genera, parasitic genes, and biological pathways. Haemonchus contortus presents a global challenge for ruminants, and the bacterial community can influence sheep's resistance and susceptibility to these parasites. Thus, a better understanding of this complex interaction could contribute to the development of a new approach to parasite control. This study evaluated the bacterial community of Corriedale sheep naturally infected with H. contortus based on the fecal egg counts over ten months and then classified as having low (LC), intermediate (IC), or high (HC). Stool samples were collected monthly for egg counts (EPG), and 16S rRNA gene sequencing was performed on five animals from each group. The average EPG was 2,635 ± 105 for HC, 845 ± 129 for IC, and 110 ± 70 for LC, with a significant difference (p = 0.0001). Firmicutes, Proteobacteria, and Spirochaetes were more abundant in the HC group. 102 bacterial genera showed significant differences between the LC and HC groups. Beta diversity was statistically different (p<0.005) for HC compared with the other two groups; also, different communities were found between LC and HC. Sediminispirochaeta, Oribacterium, Alloprevotella, Prevotellaceae_UCG-001, Prevotellaceae_UCG-003, Ruminiclostridium_6 and Ruminococcus_1were significant more abundant in LC, and IC group. Acetobacter and Methanocorpusculum had a significant reduction in the LC group. Thus, bacterial genera related to low methane emission and food efficiency were significantly present in the LC group. Therefore, a better understanding of the role of host-bacterial community-parasite interaction could contribute to improving parasite control management.

Immunomodulatory effects of Triatoma dimidiata feces on Trypanosoma cruzi infection in a murine model.

Trypanosoma cruzi infection involves transmission of metacyclic trypomastigotes through injured skin or mucosa via contaminated feces from insect vectors like Triatoma dimidiata (Latreille, 1811). Currently, there is insufficient information describing the immune response to feces naturally contaminated with metacyclic trypomastigotes. Mice subcutaneously inoculated with tissue-culture derived trypomastigotes (TCT) or T. dimidiata feces containing metacyclic trypomastigotes (MT) or previously multi-exposed (ME) with feces without metacyclic trypomastigotes and then infected with feces containing metacyclic parasites or only T. dimidiata feces (F) was studied from 15 min to three months post-infection. PCR detection of parasite DNA at the inoculation site demonstrated persistence of T. cruzi DNA up to 20 days in MT and TCT but disappeared earlier in the ME test group. A rapid spread of T. cruzi DNA to regional lymph nodes was observed in all experimental groups. A lower amount of amastigote nests in the heart with concomitant intense inflammation was noticed in ME mice in comparison to the MT group. CD4 + T cell subtypes at popliteal lymph nodes shows early Th1 and Th17 responses at seven days in ME mice, whereas Th1, Th17 and Treg predominate in MT mice after three weeks, and feces induces Th1, Th17 and Treg at a later stage. Our study shows that previous exposure to feces prior to infection with T. cruzi helps control parasitism at the inoculation site and in heart tissue, and an early induction of Th1 and Th17 T cell subtypes.

Presence of Cryptosporidium spp and other enteroparasites with pathogenic potential in hemodialysis patients: an open controlled study.

INTRODUCTION: The World Health Organization (WHO) points out that infection by enteroparasites can affect ~3.5 billion people around the world. Hemodialysis (HD) patients may be more susceptible to infections by opportunistic pathogens due to impaired immune function. We evaluated enteroparasite infection in a sample of HD-patients from two dialysis centers and in a control group. METHODS: Fecal samples were processed using the Hoffmann-Pons-Janner, Ritchie, Willis, and Rugai techniques. Patients with kidney failure from two dialysis centers undergoing HD for more than 3 months were included. The control group consisted of relatives of the patients without overt CKD. The TaqMan PCR and multiplex real-time PCR were carried out for detection of Cryptosporidium spp. and C. parvum and to differentiate the Entamoeba (E.) histolytica/E. dispar complex, respectively. RESULTS: A total of 97 HD patients and 42 controls were enrolled in the study. Fifty (51.5%) fecal samples from the HD group were positive for enteroparasites, as were 26 (61.9%) from the control group (P = 0.260). S. stercoralis was the single helminth detected and was only present in HD-patients. Coproscopy detected seven positive samples for the E. histolytica/E. dispar complex, three from HD patients and four from controls: by PCR, all samples were positive for the non-pathogenic E. dispar. Safranin-stained fecal smear slides were all negative for Cryptosporidium spp. However, by PCR, amplification for Crypstosporidium spp. was seen in six samples, all from the HD patients. Two of the species were classified as C. hominis by PCR-RFLP. CONCLUSIONS: Enteroparasite infection as detected by traditional techniques were not more prevalent in HD patients, but S. stercoralis was only found in these patients. It is noteworthy that Cryptosporidium spp. infection, also affecting only HD patients, could only be detected by molecular biology techniques.

Morphological evidence of gregarines (Phylum: Apicomplexa) in Triatoma dimidiata, Chagas disease vector in Mexico: Rediscovering Machadoella triatomae and a new intestinal gregarine.

The objective of this study was to morphologically characterize the structures suggestive of gregarines found in the feces of Triatoma dimidiata collected in five municipalities in Yucatan, Mexico. Three hundred ninety-six specimens of T. dimidiata collected during 2022 and 2023 were analyzed, of which 8.84 % (n = 35) showed evidence of infection by a gregarine in the intestine and 1.77 % (n = 7) of infection with vermiform gregarine in Malpighian tubules. With microscopic examination, it was possible to obtain measurements and micrographs that allowed the rediscovery of Machadoella triatomae (vermiform gregarine) as well as a potential new gregarine species not previously described in T. dimidiata, which, based on its morphological characteristics, could be another Schizogregarina of the genus Caulleryella (flask-shaped). Additionally, the dissections of some specimens helped correctly identify the site where these gregarines parasitized T. dimidiata. Furthermore, of the three staining techniques used in this study, Lugol's solution and Wright's stain provided greater contrast and were therefore useful for visualizing these microorganisms. Scanning electron microscopy of the new gregarine revealed the three-dimensional shape of merozoites inside and outside a ruptured meront in detail. This study provides morphological evidence of two gregarines (Phylum: Apicomplexa) parasitizing Triatoma dimidiata in multiple regions of Yucatan, Mexico. M. triatomae was isolated in Malpighian tubules, and another gregarine, possibly of the genus Caulleryella, was isolated in the intestine.

Research and characterization of Cryptosporidium spp. in the domestic cat (Felis catus): First description of C. felis in the state of Goiás and C. muris in the Midwest region of Brazil.

With the increasingly close coexistence between pets and humans, coupled with reports of Cryptosporidium cross-infection between felines and their guardians, research aimed at understanding the epidemiology of these parasites in specific regions has become necessary. The principal objective of this study was to undertake a molecular characterization of Cryptosporidium in fecal samples from felines in the state of Goiás, Brazil (which is unprecedented for the region), and to assess the risk factors involved in the infection of these animals in the aforementioned locale. A total of 95 fecal samples were collected from domestic felines in the municipality of Goiânia, Goiás, Brazil. All the animals involved were categorized by sex (male or female), lifestyle (stray or domiciled), and age (under six months or six months and older). After collection, all fecal aliquots underwent genomic DNA extraction, followed by a nested PCR (nPCR) technique targeting the 18 s rRNA gene. Subsequently, sequencing of all amplified products was performed to diagnose Cryptosporidium parasites. In addition to searching for Cryptosporidium in feces, all felines underwent serological testing for Feline Immunodeficiency Virus (FIV) antibodies (IgG) using the Enzyme-Linked Immunosorbent Assay (ELISA). Of all the fecal samples analyzed, 17.9 % (17/95) tested positive for the presence of Cryptosporidium spp. DNA, with the variable "age under six months" being the only statistically significant risk factor (p ≤ 0.05) for feline infection. C. felis was the most prevalent species, identified in 88.2 % (15/17) of the positive samples. C. muris was the second most diagnosed species, confirmed in 5.9 % (1/17) of the positive samples. Of all the feline serological samples evaluated, 48.42 % (46/95) were positive for anti-FIV IgG. It was confirmed that 75 % (3/4) of all adult animals positive for Cryptosporidium showed positive (50.00 % [2/4]) or indeterminate (25.00 % [1/4]) results for FIV. This unprecedented study provides the first report of parasites from the genus Cryptosporidium in domestic felines in the state of Goiás, including the first report of C. felis in the state and of C. muris in Midwest Brazil.

First morphological and molecular description of the ciliate protozoa Buxtonella sulcata (Ciliophora, Vestibuliferida) in cattle in Chile.

Buxtonella sulcata is an intestine ciliate protozoa whose presence in the cattle intestine has been associated with diarrhea episodes. Despite its cosmopolitan distribution, it has yet to be reported in previous studies on cattle in Chile. This study aimed to morphologically and molecularly identify cysts of Balantoides coli-like found in seven cattle samples admitted for parasitological analysis to the Laboratory of Parasitology and Parasitic Disease, Faculty of Veterinary and Livestock Sciences, University of Chile, as the ciliate Buxtonella sulcata. Seven fecal samples from three individuals from the Chimbarongo district, O'Higgins region of Chile, and four individuals from the South Campus of the University of Chile, La Pintana district, Metropolitan Region of Chile, were analyzed by sedimentation technique. Then, DNA was extracted from the positive samples, and a PCR was performed, amplifying the ITS1-5.8S-rRNA-ITS2 region. The resulting sequences were aligned with reported sequence variants for this molecular marker and other sequences available in public databases to generate a phylogenetic tree. Our result showed structures compatible with cysts of ciliate organisms in all analyzed samples. The DNA of six out of seven samples was amplified and sequenced. The nucleotide sequences obtained from the isolates correspond to B. sulcata, confirming its presence in Chile. Polymorphisms associated with sequence variants A and B of the ITS1-5.8S-rRNA-ITS2 region were identified. The phylogenetic tree showed that all isolates in the present study were similar and clustered in the same clade. Thus, the present study represents the first molecular detection of the protozoan B. sulcata in cattle in Chile.

Modulation of Eimeria spp. parasite load on productivity parameters in lambs fed with babassu byproduct.

This study investigated the modulation of Eimeria spp. parasite load and its impact on productivity parameters in lambs fed varying levels of babassu by-product (BBP). Twenty-four Dorper × Santa Inês lambs naturally infected with Eimeria spp. were divided into four groups and assigned to dietary treatments with increasing levels of BBP inclusion: Control group (0% BBP; n = 6), G1 (5% BBP; n = 6), G2 (10% BBP; n = 6), and G3 (15% BBP; n = 6). Fecal oocyst counts, dry matter intake (DMI), average daily gain (ADG), and apparent digestibility coefficients were monitored throughout the experiment. Results revealed that 9.5% BBP inclusion was associated with the lowest mean oocyst count per gram of feces, without compromising ADG. Nine Eimeria species were identified, with E. crandallis, E. parva and E. ovinoidalis being the most prevalent. Principal component analysis revealed a negative correlation between Eimeria spp. infection intensity and lamb performance, with higher BBP inclusion levels being associated with improved DMI, ADG, and digestibility. These findings suggest that dietary BBP at 9.5% inclusion effectively modulates Eimeria spp. parasite load in lambs while maintaining productivity. Although the exact mechanisms require further investigation, these results highlight BBP as a promising natural alternative for coccidiosis management in sheep production. This natural, sustainable approach offers a promising strategy for coccidiosis management in sheep, particularly in tropical and subtropical production systems.

Diversity of the Amoebozoa and Ciliophora Groups in Non-Human Primates Kept Ex Situ and in Their Handlers in Different Institutions in Brazil.

Parasitic infections in non-human primates (NHPs) kept ex situ can be caused by zoonotic protists like Balantioides coli and Entamoeba histolytica. In Brazil, little is known about these infections in neotropical species. This study aimed to identify Amoebozoa and Ciliophora groups in fecal samples through in vitro isolation and molecular analysis, mapping their distribution in Brazil. Among 511 NHP and 74 handler's fecal samples, Amoebozoa were found in 61 (11.9%) NHP samples, and Ciliophora in 6 (1.2%). Amoebic cysts were present in 12 (16.2%) human samples. Iodamoeba sp. from S. xanthosternos, E. coli from a handler, and B. coli from P. troglodytes and A. guariba were isolated in vitro. Molecular techniques identified E. dispar (34.2%), E. histolytica (5.1%), E. hartmanni (26.6%), E. coli (15.2%), Iodamoeba sp. (12.6%), E. nana (8.9%), and B. coli (7.6%). Greater protist diversity occurred in northern and southeastern regions, with E. histolytica and B. coli detected in endangered species, such as Saguinus bicolor and Alouatta guariba. Protist overlap between humans and NHPs underscores zoonotic risks. This study presents the first molecular characterization of Amoebozoa and Ciliophora in neotropical NHPs kept ex situ in Brazil, highlighting the need for improved hygiene and management protocols in primate institutions.

Application of the Sm1-7-qPCR system for identifying S. mansoni DNA in experimentally infected mice.

Schistosomiasis presents a significant public health challenge, especially in regions with inadequate sanitation. Current diagnostic methods, including the Kato-Katz technique, often lack sensitivity in detecting low parasite loads, prompting the search for more precise alternatives. This study introduces the Sm1-7-qPCR system as a highly sensitive and specific diagnostic tool for identifying S. mansoni infections. The 15 female Swiss Webster mice were infected with S. mansoni cercariae, and the data were compared with those of the nested PCR assay and Kato-Katz technique. The analytical sensitivity of the Sm1-7-qPCR system was tested using genomic DNA extracted from S. mansoni worms, which demonstrated excellent detection capability. For the analytical specificity, different parasites did not show amplification. The Sm1-7-qPCR system detected S. mansoni genomic DNA in 86.7 % of the stool samples from infected mice, surpassing the Kato-Katz method. The system showed high sensitivity and specificity, accurately quantifying parasite load in infected samples, showing promise in identifying patients with low parasite loads, and contributing to disease control efforts. In conclusion, the Sm1-7-qPCR system exhibited outstanding performance as a diagnostic tool for S. mansoni, surpassing traditional methods for detecting and quantifying parasite load. Further validation studies in low endemicity areas are recommended to enhance its integration into control and management strategies for S. mansoni infections.

Survey of parasitic fauna data from wild animals through coproparasitological diagnosis in Southern Brazil.

BACKGROUND: The proximity between people and their domestic animals with wild animal populations can result in the spread of diseases with a significant impact on public health. Infection by parasites in wildlife is considered an important bioindicator of the current state of ecosystems, and studying the epidemiology of these infections is essential for a better understanding of natural foci. However, research on parasites in southern Brazil, especially in Rio Grande do Sul (RS), is considered incipient. Therefore, in this study, we aimed to identify the parasitic fauna of wild animals in the southern region of RS through fecal parasitological diagnosis. We processed 82 fecal samples from wild animals - including birds, mammals, and reptiles - from cities within the microregion of Pelotas, using the Zinc Sulfate Centrifugal Flotation, Spontaneous Sedimentation and Oocyst Sporulation techniques. RESULTS: In 69.5% of the samples (93.1% of mammals, 47% of birds and 50% of reptiles), we found helminth eggs and/or protozoan cysts/oocysts, with strongylid-type eggs being the most frequent parasites (44.11%). Additionally, 64.9% of the positive samples were parasitized by at least one morphogroup with zoonotic agents (Taeniidae, Capillaria, Strongyloides, Spirometra, Lagochilascaris, Sarcocystis, Trichuris, Giardia, Ancilostomid, Physaloptera, Toxocara, Fasciola). We also recorded the first finding of Monocystis spp. in a Southern tamandua (Tamandua tetradactyla). CONCLUSIONS: Thus, it was observed that the majority of the animals were parasitized and, consequently, susceptible to a wide range of pathogens of medical and veterinary interest, highlighting the importance of these hosts in the spread of parasites, especially those with zoonotic potential. However, the ecology of transmission and the role of these hosts in the life cycles of parasites should be further explored in other studies.

Identification of a novel GP60 subtype family of Cryptosporidium wrairi from capybaras (Hydrochoerus hydrochaeris) inhabiting urban areas in the state of Mato Grosso do Sul, Brazil.

Capybaras (Hydrochoerus hydrochaeris) are hosts for several parasites of public health importance, including Cryptosporidium spp. Therefore, this study aimed to perform the molecular characterization of Cryptosporidium spp. in fecal samples from capybaras inhabiting urban areas. We analyzed 401 fecal samples from capybaras in two municipalities of the state of Mato Grosso do Sul, Brazil. Fecal samples were purified using centrifugal sedimentation with ethyl acetate. They were then screened for Cryptosporidium spp. by malachite green negative staining and a nested PCR protocol targeting the 18S rRNA gene. Samples positive by microscopy or PCR were examined by PCR protocols targeting the actin, HSP-70, and GP60 genes. Amplicons from all PCR protocols were subjected to genetic sequencing. Microscopic screening and 18S rRNA gene-targeted PCR identified 0.25 % (1/401) and 0.5 % (2/401) of samples, respectively, as positive for Cryptosporidium spp. The genetic sequences of the 18S rRNA, HSP-70, actin, and GP60 genes showed genetic similarity to Cryptosporidium wrairi sequences of 99.07 %, 99.69 %, 99.57 %, and 91.51 %, respectively. Genetic sequencing and phylogenetic analyses identified the novel GP60 subtype family VIIbA13 of C. wrairi. In conclusion, we report in this study a low prevalence of the novel GP60 subtype family VIIbA13 of C. wrairi in free-living capybaras from urban areas of the state of Mato Grosso do Sul, Brazil. We propose that capybaras act as a novel host for C. wrairi.

Identification of Ancylostoma caninum in Domestic Dogs from Ecuador via Various Techniques.

BACKGROUND Ancylostoma caninum is a soil-borne, soil-transmitted helminth with infective larvae and produces cutaneous larva migrans in humans. The objective of this study was to confirm the presence of A. caninum in domestic dogs from the urban-marginal and rural sectors of the Ecuadorian coast through morphometry, culture, and molecular techniques. MATERIAL AND METHODS A total of 498 domestic dogs were analyzed via 5 coproparasitic screening methods: direct, modified flotation, sedimentation with centrifugation using saline solution (identification of eggs), and modified Baermann and Harada-Mori methods (identification of larvae). For confirmation, culture (agar in plates, Müller-Hinton agar plates, MacConkey agar plates, and artisanal media with sand and/or ravine soil, both sterile, and all prepared in Petri dishes), polymerase chain reaction (PCR), and DNA sequencing analyses were subsequently conducted via morphometric methods. RESULTS A total of 250 domestic dogs were diagnosed with A. caninum (50.20%) via coproparasitic methods. The parasite was subsequently confirmed via morphometry, cultured in 5 culture media, and detected by PCR, and phylogenetic characterization was performed. CONCLUSIONS The coproparasitic methods used for screening increased the sensitivity of the results. Morphometry is an easily accessible and low-cost confirmatory method. The culture method was used to test the good adaptability of and infection by the parasite. The presence of A. caninum was detected for the first time via PCR, and its phylogenetic profile was analyzed using the molecular marker cox1.

Seroconversion and seroreversion rates of anti-Strongyloides IgG in rural areas of the Amazon: a population-based panel study.

Using a panel study design, we aimed to estimate the seroconversion and seroreversion rates of anti-Strongyloides IgG antibodies from surveys carried out 11 months apart in a rural community in the Amazon Basin in Brazil. We used enzyme immunoassays to measure anti-Strongyloides IgG antibodies in 325 baseline plasma samples and 224 others that were collected 11 months later from residents in the agricultural settlement of Granada, Acre State. We observed anti-Strongyloides IgG antibodies in 21.8% of the baseline samples (which showed that 3.4% of participants had larvae in their stool) and in 23.7% of the follow-up samples. The seroconversion rate estimated at 9.7 episodes/100 person-years at risk agrees with ongoing transmission. Specific antibodies were relatively short-lived and nine (25.0%) of 36 seropositive participants at baseline were seronegative when retested 11 months later. Fecal surveys can severely underestimate the prevalence of S. stercoralis infection in rural Amazonians. Serology provides a field-deployable diagnostic tool to find high-prevalence populations, identify associated risk factors, and monitor intervention programs.

Impact of Fasciola hepatica Infection and Triclabendazole Treatment on Humoral Immune Response in Cattle.

Fasciola hepatica is a trematode parasite of significant veterinary and public health importance, causing economic losses in livestock due to liver damage, weight loss and reduced milk production. Although triclabendazole (TCZ) is available for treatment, it does not prevent the disease or reinfection. Infected animals exhibit strong immunoregulation, increasing susceptibility to secondary infections and altering vaccine-induced antibody responses. This study investigates the humoral immune response in cattle infected with F. hepatica at different stages of infection and evaluates the effect of TCZ treatment on this response. It also examines how fasciolosis affects the antibody response induced by bacterial vaccines during early and chronic infection stages. Experimental infections in steers were conducted, with faecal and plasma samples collected at various intervals. The results showed a decrease in parasite-specific antibody avidity during infection. However, F. hepatica infection did not substantially modify antibody response to bacterial vaccines. This study underscores the need for further research on the impact of fasciolosis and its treatment on livestock vaccination efficacy.

First report of a morulated Ascaridoidea (Nematoda) egg in an avian coprolite from the Paleogene of the Paraíba Valley, State of São Paulo, Brazil.

Ascaridoidea (Nematoda) is a widespread superfamily of nematodes that comprises gastrointestinal parasites from all major groups of vertebrates. Although this taxon probably emerged in the Carboniferous, its Brazilian fossil record includes mostly eggs, found in ancient remains, collected in paleontological and archeological sites from the Mesozoic and Cenozoic Eras. The Tremembé Formation (Oligocene of the Taubaté Basin) has become an important source for paleoparasitological studies in avian coprolites during the third decade of the 21st century, with reports of eggs only at only a single cell stage, of embryonic development. Here we present the first egg of Ascaridoidea preserved containing morula, from a bird coprolite recovered from the shales of the Tremembé Formation. Three coprolites, from the outcrop of Aligra Comércio de Argila S/A, Taubaté municipality (State of São Paulo), were rehydrated and subjected to spontaneous sedimentation. Based on morphological and morphometric features and diet and zoopaleontological context, the trace fossils were assigned to piscivorous birds. The egg found showed morphological characteristics typical of Ascaridoidea: namely spherical form, ornamented, and somewhat thick shell. Moreover, this superfamily includes several taxa that infect piscivorous birds and fish in heteroxenous life cycles and produce eggs with similar features as the egg found in the present study. The paleoparasitological information associated with the paleofaunistic diversity of birds and fish from the Tremembé Formation, reveal that the ancient Brazilian paleoenvironments provided subsidies for the rise and success of nematodes infecting these animals during the Paleogene.

Prevalence of intestinal parasites in street dwellers attending a shelter in Cali, Colombia. / Prevalencia de parásitos intestinales en habitantes de calle atendidos en un hogar de paso de Cali, Colombia

INTRODUCTION: Intestinal parasitic infections represent a public health problem, especially among vulnerable populations. There are few studies on the prevalence and determinants of intestinal parasites infections in street dwellers, who may experience significant health and socioeconomic implications. Understanding the prevalence and associated factors of intestinal parasites in this population is crucial for targeted interventions to mitigate the spread of these infections. OBJECTIVE: To determine the prevalence of intestinal parasites in street dwellers attending a shelter in Cali, Colombia. MATERIALS AND METHODS: We selected 66 participants who met the inclusion criteria. We collected serial stool samples for laboratory evaluation and sociodemographic data, and information on their hygiene habits and addictions. RESULTS: Seventy-six percent of the participants had intestinal parasites or commensals, with 30% presenting monoparasitism, 46% polyparasitism, and 20% eosinophilia. Blastocystis spp. was the most common organism (68.18%), followed by Endolimax nana (34.85%) and Entamoeba coli (18.18%). The most common pathogens were the Entamoeba histolytica/E. dispar/E. moshkovskii complex (10.61%) and hookworms (9.09%). We evaluated prevalence-related determinants. CONCLUSIONS: Intestinal parasitism is a health problem among street dwellers in Cali. A serial examination is recommended for diagnosing intestinal parasitic infection, especially in cases of low parasite loads. Campaigns should be established to reduce the prevalence of these parasites in populations at risk of complications.

Introducción: Las enteroparasitosis representan un importante problema de salud pública, especialmente entre poblaciones vulnerables. Hay pocos estudios sobre la prevalencia y los factores determinantes relacionados con la presencia de enteroparásitos en habitantes de calle, quienes pueden sufrir complicaciones de salud e implicaciones socioeconómicas significativas. Por lo tanto, comprender la prevalencia y los factores asociados con los enteroparásitos en esta población, es crucial para desarrollar intervenciones dirigidas y mitigar la propagación de estas infecciones. Objetivo: Determinar la prevalencia de enteroparásitos en habitantes de calle que acuden a un hogar de paso en Cali, Colombia. Materiales y métodos: Se seleccionaron 66 participantes que cumplían con los criterios de inclusión y se recolectaron muestras seriadas de materia fecal para su evaluación en el laboratorio. Se recopiló información sociodemográfica y datos sobre hábitos de higiene y adicciones de los participantes. Resultados: El 76 % de los participantes presentó parásitos o comensales intestinales: el 30 % tenía monoparasitismo, el 46 %, poliparasitismo, y el 20%, eosinofilia. Blastocystis spp. fue el organismo más frecuente (68,18 %), seguido por Endolimax nana (34,85 %) y Entamoeba coli (18,18 %). Entre los agentes patógenos, los más comunes fueron el complejo Entamoeba histolytica/E. dispar/E. moshkovskii (10,61 %) y las uncinarias (9,09 %). Se evaluaron los factores determinantes relacionados con estas prevalencias. Conclusiones: El parasitismo intestinal sigue siendo un problema importante en grupos vulnerables, como los habitantes de calle en Cali. Se recomiendan exámenes seriados para el diagnóstico de las parasitosis intestinales, especialmente en casos de bajas cargas parasitarias. Es necesario establecer campañas para disminuir la prevalencia de estos parásitos en poblaciones con riesgo de complicaciones.

Giardia lamblia risk factors and burden in children with acute gastroenteritis in a Nicaraguan birth cohort.

BACKGROUND: Giardia lamblia is an intestinal protozoan estimated to cause ~200 million symptomatic infections annually, mainly in children in low- and middle-income countries associated with intestinal damage, increased permeability, and malabsorption. METHODS AND RESULTS: We describe here the epidemiology, incidence, clinical characteristics, and risk factors of acute gastroenteritis episodes (AGE) with G. lamblia detection (GAGE) using a birth cohort of 443 Nicaraguan children followed weekly until 36 months of life. From June 2017 to July 2021, 1385 AGE samples were tested by qPCR. G. lamblia was detected in 104 (7.5%) of AGE episodes. In all, 69 (15.6%) children experienced at least one GAGE episode, and 25 of them (36.2%) experienced more than one episode. The incidence rate of the first episode of GAGE was 6.8/100 child-years (95% CI, 4.5-9.1). During GAGE, bloody stools, vomiting, and fever were uncommon, and children were less likely to be treated at a primary care clinic, suggesting that GAGE is typically mild and most cases did not receive medical attention, which could facilitate higher parasite loads with increased possibilities of establishing chronic carriage. GAGE was more common in children 12-24 months of age (13.9/100 child-years [95% CI, 10.7-17.1]) as compared to other age groups. In our birth-cohort, children living in a home with an indoor toilet (aHR, 0.52 [95%CI, 0.29-0.92]), and being breastfed in the first year of life (aHR: 0.10 [95%IC, 0.02, 0.57]) had a lower incidence of GAGE. In contrast, being breastfed for ≤ 6 months was associated with a higher incidence if the children were living in houses without indoor toilets and earthen floors (HR, 7.79 [95% CI, 2.07, 29.3]). CONCLUSION: Taken together, GAGE is more frequent under poor household conditions. However, breastfeeding significantly reduces the incidence of GAGE in those children.

A comparison of the diagnostic capability of Kato-Katz and real-time PCR for the assessment of treatment efficacy of ivermectin and albendazole combination against T. trichiura infections.

BACKGROUND: Trichuris trichiura is humans' second most prevalent soil-transmitted helminth (STH) infection after Ascaris lumbricoides, affecting approximately 460 million people worldwide. Despite its sub-optimal sensitivity, especially in low prevalence and infection intensity settings, the modified Kato-Katz (K-K) is still recommended as a diagnostic method by the World Health organization (WHO) guidelines. METHODOLOGY/PRINCIPAL FINDINGS: Within a randomized clinical trial (RCT) comprising four treatment arms with two different anthelmintics, the present study reports an important secondary research objective to determine the diagnostic agreement between K-K and real-time PCR evaluating treatment efficacy against T. trichiura. The parasitological results were analyzed, including cure rates (CR) of a subgroup of 94 participants positive at baseline for T. trichiura eggs for both techniques. The single-dose albendazole (ALB) arm resulted in significantly lower CRs than experimental arms of albendazole/ivermectin (ALB/IVM) combinations. The overall diagnostic agreement between both techniques was 88.7% [κ = 0.8 (P<0.001)]. Concordance between eggs per gram and Ct values was moderate, with the discordance source likely stemming from lighter infection intensities. CONCLUSIONS AND SIGNIFICANCE: These findings indicate that real-time PCR is a suitable alternative for CR estimation in helminthiasis clinical trials. It also highlights the need to identify the most accurate diagnostic tools for RCTs, that would benefit from guiding principles to achieve harmonization across studies and are not necessarily the same as those used for epidemiological surveys. TRIAL REGISTRATION: Clinical Trials.gov (NCT04041453).

Gray foxes (Urocyon cinereoargenteus) as natural definitive hosts of Paragonimus mexicanus.

Paragonimus mexicanus is a trematode that causes pulmonary and extrapulmonary infections in humans, characterized by chest pain, dyspnea, fever, and weight loss. The detection of Paragonimus spp. is primarily achieved through the microscopic observation of eggs in feces, sputum, and pleural fluid. Paragonimus mexicanus has been found in various wild animals, including dogs, cats, raccoons, and opossums. Although the reservoirs of P. mexicanus in Costa Rica are unknown, this study analyzed fecal samples from gray foxes (Urocyon cinereoargenteus) using microscopic and molecular methods. In the morphological analysis, characteristic eggs of the genus Paragonimus were identified. DNA was extracted from fecal samples, and a fragment of the ITS2 loci of trematodes was amplified, which showed a 100 % similarity with P. mexicanus metacercariae from crabs in Ecuador. Then, a Bayesian inference phylogenetic analysis was performed with the obtained data and pre-existing sequences of P. mexicanus found in America, showing that our sequence clustered firstly with others from Colima and Veracruz (Mexico), and Ecuador, while a second cluster contained sequences from Chiapas (Mexico), Ecuador, and Guatemala. These results provide evidence of the presence of P. mexicanus in the gray fox and suggest its role as a possible new wild reservoir, which could have zoonotic implications for the infection of other animal species and humans. Additionally, our phylogenetic analysis reveals low genetic differentiation among the compared P. mexicanus populations and the possibility of additional Paragonimus species currently classified as P. mexicanus. The finding of this parasite in our country, together with comparisons with previous studies, highlights the complex evolutionary history and population dynamics of P. mexicanus.

Eurytrematosis: An emerging parasitosis in cattle from Northeast Argentina.

This study was carried out in the northwest region of Misiones Province, Argentina, focusing on the clinical, pathological, epidemiological, and parasitological aspects of Eurytrema spp. in cattle. Clinical monitoring of five cattle cases exhibiting chronic weight loss revealed that affected animals had enlarged pancreases, with severe fibrosis and presence of Eurytrema coelomaticum in the pancreatic ducts. Histopathological analysis confirmed severe fibrosing periductal lymphoplasmacytic interstitial pancreatitis with intralesional trematodes. A cross-sectional epidemiological study was conducted from June 2018 to May 2021, involving 44 farms and 718 fecal samples. Coproparasitological analysis revealed a within-farm prevalence of 70.7 %, with an animal-level prevalence of 37.5 %. A multivariable generalized linear model identified the abundance of snails, the limited availability of monthly veterinary assistance, and loss of body condition as significant risk factors for Eurytrema sp. prevalence. Spatial analysis detected three significant clusters with varying prevalence levels, highlighting areas of high and low parasite occurrence. This study represents the first detailed investigation of Eurytrema sp. in Argentina, confirming its endemic presence in the central-northern region of Misiones Province. The findings underscore the need for further research to evaluate the parasite's spread across the province and its potential impact on livestock production.