Bovine sarcocystosis: Sarcocystis species,diagnosis, prevalence,economic and public health considerations,and association of Sarcocystis species with eosinophilic myositis in cattle

Infections by Sarcocystis in cattle are ubiquitous worldwide. There is considerable debate concerning the identity of Sarcocystis spp. in cattle. Proper diagnosis of Sarcocystis spp. is important to assess their economic and public health importance. Currently there are seven named species: Sarcocystis hirsuta, Sarcocystis cruzi, Sarcocystis hominis, Sarcocystis bovifelis, arcocystis heydorni, Sarcocystis bovini and Sarcocystis rommeli. Additionally, there are unnamed Sarcocystis spp. Two species, S. hominis and S. heydorni, are zoonotic. One out of seven species (S. hirsuta, contracted from cats) forms macroscopic cysts which can be visible during carcass inspection. Current molecular characterization is based on DNA extracted from sarcocysts from naturally infected cattle because DNA was not characterized from tissues of experimentally infected cattle or feces of experimentally infected definitive hosts. Sarcocystis cruzi (transmitted via canids) is recognized as the most pathogenic species and it causes abortion, low milk yield, poor body growth, and outbreaks of clinical sarcocystosis and death. Additionally, Sarcocystis infections have been linked to an inflammatory condition of striated muscles termed bovine eosinophilic myositis (BEM). Cattle affected by BEM appear clinically normal. Diagnosis of BEM at slaughter occurs when inspecting the carcass surface, or once the carcass has been divided into prime cuts or quarters. Sex and breed have no apparent influence on prevalence of BEM. The condition evidently occurs with equal frequency in steers, cows, and heifers. Virtually all striated muscles can be affected including skeletal muscles, the muscles of the eye, larynx, and the heart. In the USA, regulations require condemnation of BEM-affected parts, or (in severe cases) the entire carcass. These aesthetic considerations result in economic losses. Cattle experimentally infected with Sarcocystis did not have BEM at slaughter. Here, we review the status of Sarcocystis spp. and BEM in cattle including prevalence, lesions, epidemiology, and association of BEM with different species of Sarcocystis.     

Infection survey and morphological characteristics of Sarcocystis spp. in naturally infected Tibetan sheep from Qinghai in northwestern China

Sarcocystosis is a parasitic disease caused by intracellular coccidian protozoans that belong to the genus Sarcocystis. These parasites can cause diseases of the nervous system, abortion and economically significant losses in host animals. Previous studies have reported that Sarcocystis is found in mammals, birds and reptiles, while molecular and morphological studies of infected Tibetan sheep have not been performed in the Qinghai region. The aim of this study was to determine the prevalence of Sarcocystis spp. in Tibetan sheep in Qinghai, northwestern China. The results showed that in 1155 samples, sarcocysts from unspecified species were found in 50% (577/1155) of the sheep tissues by microscopy detection. The positive rates of sarcocysts in the diaphragmatic, esophageal and cardiac muscles were 78.4% (175/223), 29.1% (207/711), and 88.2% (195/221), respectively. Ultrastructural features were exclusively observed in Sarcocystis gigantea in the esophageal tissues. The specific architecture was characterized as a space between the two layers of the original capsule wall, which was filled with fiber bundles and tissue fluid. Cauliflower-like protrusions of the original capsule wall were observed toward the outer surface of the capsule. Prominent protrusions contained fibers and matrix. In addition, the Sarcocystis 18S rRNA genes from 6 esophageal tissue samples were cloned, sequenced, and aligned to related sequences from GenBank. All 5 S. gigantea sequences examined in this study were grouped into the same cluster and belonged to the same genotype. The other 5 Sarcocystis tenella sequences were obtained from cardiac muscle and diaphragm muscle and belonged to the same clade. Overall, this study revealed a high infection rate of Sarcocystis in Tibetan sheep in the region. The results of this study may provide a reference for further research investigating the sarcocystosis epidemic in Qinghai, China.     

Molecular characterization of Sarcocystis spp. in seabirds from southern Brazil

Sarcocystis spp. are cyst forming apicomplexan parasites that infect many vertebrates including birds. Sarcocystis spp. infection was investigated in tissue samples (pectoral muscles, heart, and brain) of 47 dead seabirds collected from the coastline of Santa Catarina State SC – Brazil, between August 2019 and March 2020. A portion of each tissue was fixed in 10% buffered formalin for histopathologic analysis while DNA was extracted from another portion and screened using nested-PCR targeting ITS1. Based on molecular analysis, Sarcocystis spp. were identified in 15/47 (31.9%) seabirds of five species, kelp gull (Larus dominicanus), manx shearwater (Puffinus puffinus), neotropic cormorant (Phalacrocorax brasilianus), brown booby (Sula leucogaster) and great skua (Stercorarius skua). Microscopically visible sarcocysts were observed only in the pectoral muscle of four seabirds 8.5% (4/47), while in one brown booby, sarcocysts were seen in both pectoral and cardiac muscles. Two types of sarcocysts, thin walled (≤1 μm) and thick-walled (≥ 2 μm) were identified. Based on ITS1 sequence comparison, S. halieti, S. falcatula and three not yet described Sarcocystis spp. were detected. Phylogenetically, S. falcatula isolates were classified as two distinct clusters. This is the first confirmation of S. halieti in seabird's species in South America and S. falcatula in birds of the order Charadriiformes. Further molecular studies are needed to understand the epidemiology of the Sarcocystis spp. infection and its impact on the health of seabirds.     

Molecular identification targeting cox1 and 18S genes confirms the high prevalence of Sarcocystis spp. in cattle in the Netherlands

The reported prevalence of Sarcocystis infection in cattle in Europe ranges between 66 and 94%. Although in the Netherlands a prevalence of 100% was reported in 1993, this study aimed to develop a method for sensitive and specific molecular detection and species identification of Sarcocystis spp., in order to provide more recent data on the prevalence and identification of these protozoa in cattle meat intended for human consumption in the Netherlands. For this purpose, 104 cattle samples were obtained from Dutch slaughterhouses. Genomic DNA was extracted, and analysed by 18S and cox1 PCR. Magnetic capture was used to extract and amplify 18S-specific DNA. Sarcocystis DNA was detected in 82.7% of the samples. PCR amplicons of both targets were sequenced, and sequence identities of ≥97% were observed for Sarcocystis cruzi (65.4%), Sarcocystis hominis (12.5%), Sarcocystis bovifelis (8.7%), Sarcocystis hirsuta and Sarcocystis heydorni (both 1.0%). Mixed infections were observed in 17.3% of the samples. The magnetic capture was not significantly more sensitive compared with standard DNA extraction, but magnetic capture did add to the overall sensitivity. Using cox1 sequencing, all species are clearly distinguished, whereas for 18S the variation between species is limited, which particularly hampers reliable identification of thick walled Sarcocystis spp. Furthermore, the detection of 12.5% S. hominis and 1% S. heydorni points towards an established transmission route between cattle and humans in the Netherlands. The availability of four additional well-identified and well-referenced S. hominis cox1 sequences in public databases enables development of species-specific diagnostic PCRs targeting cox1, which in combination with magnetic capture could provide the means to determine the prevalence of human sarcocystosis.     

Sarcocystis rommeli,n. sp. (Apicomplexa: Sarcocystidae) from Cattle (Bos taurus) and its Differentiation from Sarcocystis hominis

Cattle (Bos taurus) are intermediate hosts for three named species of Sarcocystis, S. cruzi, S. hirsuta, and S. hominis. Recently, a fourth species was identified and named S. sinensis. However, S. sinensis originally named a species of Sarcocystis in water buffalo (Bubalus bubalis) in China. Based on unverifiable evidence, it was suggested that the same parasite infects cattle. In addition, S. sinensis was recently declared as nomen nudum because its naming violated the rules of International Code of Zoological Nomenclature. Thus, the fourth species using cattle as an intermediate host does not have a valid name. Here, we propose a new name, Sarcocystis rommeli for the S. sinensis‐like parasite from cattle in Argentina, and differentiate it ultrastructurally from S. hominis sarcocysts from experimentally infected cattle. Sarcocystis rommeli sarcocysts were microscopic with a 5‐μm‐thick wall with slender villar protrusions (Vp); the Vp were up to 5 μm long, up to 0.5 μm wide, and of uneven thickness, often bent at an angle. The ground substance layer (Gs) was up to 0.8 μm thick and smooth. Vesicular structures were seen at the base of the Vp. The bradyzoites were 10–12 μm long. Sarcocystis hominis sarcocysts had Vp that were often upright, up to 7.5 μm long, and up to 1.8 μm wide; the Gs was up to 2 μm thick and without vesicles. Its sarcocyst wall was up to 5.6 μm thick, the vp were bent at an angle, up to 5.8 μm long, the Gs was up to 2 μm thick, but without vesicles seen in S. rommeli. Beef containing sarcocysts of S. rommeli was not orally infectious for two human volunteers and a red fox (Vulpes vulpes). The Sarcocystis described here is molecularly different from S. cruzi, S. hirsuta, and S. hominis based on 18S rRNA and cox1 gene sequences.     

Molecular identification of two Sarcocystis species in fallow deer (Dama dama) from Lithuania

Due to the lack of molecular research conducted, little is known about Sarcocystis species diversity in the fallow deer (Dama dama). Until now, Sarcocystis jorrini and Sarcocystis morae were described to form sarcocysts in the muscles of this host. In the present study diaphragm muscle samples of free-ranging fallow deer from Lithuania were investigated for Sarcocystis species. Sarcocysts were detected in 39 out of 48 (81.3%) fallow deer examined. Under a light microscope two types of sarcocysts having hair-like and finger-like protrusions were observed. Based on DNA sequence analysis of cox1 and 18S rDNA, two species, S. morae and Sarcocystis entzerothi were identified. In prior studies, the latter species was only detected in Lithuanian roe deer (Capreolus capreolus) and in sika deer (Cervus nippon). The haplotype network of S. morae sequences specified close relationships between haplotypes found in the same country. According to current knowledge, the fallow deer is characterised by low Sarcocystis species richness as compared with other cervid species from Europe.     

Sarcocystis and Its Complications in Camels (Camelus dromedarius) of Eastern Provinces of Iran

The prevalence of Sarcocystis spp. was investigated by gross and histopathological examinations in 250 camels (Camelus dromedarius) slaughtered from 2002 to 2005 in the Mashhad Slaughterhouse, eastern Iran. Samples were taken from the diaphragm, heart, tongue, esophagus and masseter muscles for histopathological studies. No macroscopic sarcocysts were found in the samples at gross inspection. Sarcocysts were detected in 209 of 250 (83.6%) examined camels at histopathological level. The infection rate of the esophagus, heart, masseter muscles, diaphragm, and tongue was 58.8%, 48.0%, 46.8%, 41.6%, and 28.0%, respectively. There was no significant difference in the rate of infection between male (85.8%) and female (81.0%) camels. The tissue response to vital cysts was minimal; however, reaction to the degenerating cysts was severe and caused tissue damages resulting in hyperemia, hemorrhages, mononuclear cell infiltration, necrotic changes, and fibrosis. The wild and domestic carnivores especially dogs may be the final hosts of Sarcocystis spp. in this area.     

Sarcocystosis among Wild Captive and Zoo Animals in Malaysia

Sarcocystis sp. infection was investigated in 20 necropsied captive wild mammals and 20 birds in 2 petting zoos in Malaysia. The gross post-mortem lesions in mammals showed marbling of the liver with uniform congestion of the intestine, and for birds, there was atrophy of the sternal muscles with hemorrhage and edema of the lungs in 2 birds. Naked eye examination was used for detection of macroscopic sarcocysts, and muscle squash for microscopic type. Only microscopically visible cysts were detected in 8 animals and species identification was not possible. Histological examination of the sections of infected skeletal muscles showed more than 5 sarcocysts in each specimen. No leukocytic infiltration was seen in affected organs. The shape of the cysts was elongated or circular, and the mean size reached 254 × 24.5 µm and the thickness of the wall up to 2.5 µm. Two stages were recognized in the cysts, the peripheral metrocytes and large numbers of crescent shaped merozoites. Out of 40 animals examined, 3 mammals and 5 birds were positive (20%). The infection rate was 15% and 25% in mammals and birds, respectively. Regarding the organs, the infection rate was 50% in the skeletal muscles followed by tongue and heart (37.5%), diaphragm (25%), and esophagus (12.5%). Further ultrastructural studies are required to identify the species of Sarcocystis that infect captive wild animals and their possible role in zoonosis.     

Genetic characterisation by isoenzyme markers of North American and Australasian isolates of species of Sarcocystis (Protozoa: Apicomplexa) from mice,sheep, goats and cattle

The technique of isoenzyme (enzyme isotype) electrophoresis was used to compare genetic profiles of extracts of zoites of sarcocysts from North America and Australasia. The species examined were Sarcocystis muris (Railliet, 1886) from mice, S. gigantea (Railliet, 1886) (syn. S. ovifelis Heydorn et al., 1975) from sheep, S. capracanis Fischer, 1979 from goats and S. cruzi (Hasselmann, 1923) (syn. S. bovicanis Heydorn et al., 1975) from cattle. Sarcocysts from the four host animals had different alleles at almost all loci studied. This was not affected by having a common definitive host. Extracts of two cat-borne Sarcocystis species shared alleles at only 3 out of 16 loci, while two dog-borne Sarcocystis species had different alleles at 8 out of 16 loci. The extent of genetic divergence among sarcocysts confirmed the existance of distinct species in each host sampled. By contrast, the isolates from the United States of America and Australasia for any particular host were essentially identical, sharing at least one allele at every locus tested. ac]19860908     

Molecular survey and characterization of Theileria annulata and Ehrlichia ruminantium in cattle from Northwest China

Theileriosis and ehrlichiosis are two important tick-borne diseases affecting cattle farming in China. However, limited information is available regarding prevalence and molecular characterization of Theileria annulata and Ehrlichia ruminantium in cattle in Xinjiang Uygur Autonomous Region (XUAR), northwestern China. In this study, a total of 176 blood samples of cattle from three rural areas of XUAR were collected in June 2017 and were tested by nested-PCR. A total of 34 (19.3%) samples were found to be infected with one or two pathogens. The overall prevalence rates of T. annulata and E. ruminantium were 18.2% and 1.7%, respectively. Phylogenetic analyses revealed that the E. ruminantium isolates from XUAR were located in the same clade but diverged from the isolates from African countries using pCS20 gene while T. annulata isolates from XUAR revealed differences in the genotypes using Tams1 sequences. To our knowledge, this is the first report of E. ruminantium infection in cattle in China. It also provides the first genetic characterization of T. annulata in cattle in XUAR. The current findings are important for understanding the distribution of agents of theileriosis and ehrlichiosis and in designing measures for the prevention and control of tick-borne diseases in cattle, other animals, and humans.     

Molecular identification of seven Sarcocystis species in red deer (Cervus elaphus) from Lithuania

The diaphragm muscles of 77 free-ranging red deer (Cervus elaphus) were examined for Sarcocystis species in Lithuania. Sarcocysts were detected in 61 out of 77 (79.2%) animals investigated. A total of 60 isolated sarcocysts were identified to species using subunit I of cytochrome c oxidase (cox1) sequence analysis. Overall, seven species, S. entzerothi, S. hjorti, S. iberica, S. linearis, S. pilosa, S. truncata and S. venatoria, were confirmed in Lithuanian red deer. Sarcocystis entzerothi was reported in red deer for the first time. Previously this species was shown to use sika deer as well as roe deer and fallow deer as an intermediate host. Based on cox1, with the addition of the current data, altogether 13 Sarcocystis species have so far been shown to use red deer as an intermediate host. Species detected in red deer demonstrated considerable differences in intraspecific genetic variation at cox1. Genetic distances between different samples of S. hjorti and S. linearis were calculated using principal coordinates analysis (PCoA), implying molecular divergence of same Sarcocystis species using different hosts in the same geographical area and divergence of those employing same intermediate host species from different areas.     

Trypanosoma cruzi maxicircle heterogeneity in Chagas disease patients from Brazil

The majority of individuals in the chronic phase of Chagas disease are asymptomatic (indeterminate form, IF). Each year, ∼3% of them develop lesions in the heart or gastrointestinal tract. Cardiomyopathy (CCHD) is the most severe manifestation of Chagas disease. The factors that determine the outcome of the infection are unknown, but certainly depend on complex interactions amongst the genetic make-up of the parasite, the host immunogenetic background and environment. In a previous study we verified that the maxicircle gene NADH dehydrogenase (mitochondrial complex I) subunit 7 (ND7) from IF isolates had a 455 bp deletion compared with the wild type (WT) ND7 gene from CCHD strains. We proposed that ND7 could constitute a valuable target for PCR assays in the differential diagnosis of the infective strain. In the present study we evaluated this hypothesis by examination of ND7 structure in parasites from 75 patients with defined pathologies, from Southeast Brazil. We also analysed the structure of additional mitochondrial genes (ND4/CR4, COIII and COII) since the maxicircle is used for clustering Trypanosoma cruzi strains into three clades/haplogroups. We conclude that maxicircle genes do not discriminate parasite populations which induce IF or CCHD forms. Interestingly, the great majority of the analysed isolates belong to T. cruzi II (discrete typing unit, (DTU) IIb) genotype. This scenario is at variance with the prevalence of hybrid (DTU IId) human isolates in Bolivia, Chile and Argentina. The distribution of WT and deleted ND7 and ND4 genes in T. cruzi strains suggests that mutations in the two genes occurred in different ancestrals in the T. cruzi II cluster, allowing the identification of at least three mitochondrial sub-lineages within this group. The observation that T. cruzi strains accumulate mutations in several genes coding for complex I subunits favours the hypothesis that complex I may have a limited activity in this parasite.     

Molecular phylogeny of Sarcocystis fayeri (Apicomplexa: Sarcocystidae) from the domestic horse Equus caballus based on 18S rRNA gene sequences and its prevalence

Sarcocystosis is a parasitic disease caused by an intracellular protozoan parasite Sarcocystis belonging to the phylum Apicomplexa. These parasites have a requisite two-host life cycle. Recently, there are many Sarcocystis species that identified morphologically. In the present study, diaphragmatic muscle samples from the domestic horse (Equus caballus) were examined for Sarcocystis infection. The natural infection with sarcocysts was recorded to be 62·5% for only microcysts in the infected muscles. Molecular analysis using the 18S rRNA gene was conducted to swiftly and accurately identify the recovered species. Studies on the expression of the 18S rRNA gene have confirmed that the present parasite isolates belong to the Sarcocystis genus. The sequence data showed significant identities (>80%) with archived gene sequences from species within the Sarcocystidae family, and a dendrogram showing the phylogenetic relationship was constructed. The most closely related species were the previously described Sarcocystis fayeri and Sarcocystis bertrami. The current data showed that the present species was identified as S. fayeri and deposited in GenBank (accession number MF614956.1). This study highlights the importance of the genetic data in the exact taxonomy within sarcocystid species.     

Sarcocystis eothenomysi n. sp. (Apicomplexa: Sarcocystidae) from the large oriental vole Eothenomys miletus (Thomas) (Cricetidae: Microtinae) from Anning,China

Fifty-six oriental voles, Eothenomys miletus (Thomas), were collected in Anning prefecture of Yunnan Province (China) between March 2012 and December 2013 and examined for the presence of sarcocysts. Sarcosysts of a new species, Sarcocystis eothenomysi n. sp., were found in 14 out of 56 E. miletus (25%); they possessed a striated cyst wall, c.1–2 μm thick. Under transmission electron microscopy the cysts of S. eothenomysi exhibited numerous small, irregular protrusions, which may appear T-shaped in some sections. A phylogenetic analysis based on 18S rRNA gene sequences indicated that S. eothenomysi shares closest affinity with those species of Sarcocystis Lankester, 1982, which use cobra or viperid snakes as definitive hosts. We therefore, hypothesise that a venomous snake may serve as the definitive host for S. eothenomysi. This is the first species of Sarcocystis reported from Eothenomys spp.     

Morphological and Biochemical Correlates in the Characterization of Sarcocystis spp.1

ABSTRACT. Isoenzyme electrophoretic techniques were applied to the characterization of seven Sarcocystis spp. that had been identified by conventional morphological studies. Cystozoites were harvested from macroscopic cysts from sheep, cattle, and mice and from microscopic cysts from sheep, cattle, and goats. Soluble cystozoite extracts were subjected to cellulose acetate gel electrophoresis and characterized at 15 of the 39 enzyme loci examined. Genetic relationships among isolates were examined by simple phenetic clustering. Two different morphological types of macroscopic cysts from sheep, identified as S. gigantea (syn. S. ovifelis) and S. medusiformis, consistently differed at 40% of the loci examined. Such genetic divergence confirms their separate morphotypic classification. Both differed from microscopic cyst isolates from sheep at 87% of the loci examined; however, two different morphotypes of microscopic cysts were found in the sheep sampled (thick-walled and thin-walled cysts). Until sufficient numbers of each type can be isolated and examined separately, both were regarded as belonging to the species S. tenella (syn. S. ovicanis). Macroscopic and microscopic cysts from cattle consistently differed at 80% of the loci thereby supporting their separate classification as S. hirsuta (syn. S. bovifelis) and S. cruzi (syn. S. bovicanis), respectively. Isolates from goats (microscopic cysts identified as S. capracanis) differed from S. tenella and S. cruzi at 20% and 47% of the loci, respectively. All macroscopic cyst isolates from the various host animal species (including S. muris from mice) differed from each other at nearly all loci. Isoenzyme electrophoretic techniques therefore provided genetic evidence supporting the classification of these various Sarcocystis spp. by their morphological characteristics.     

Real Time PCR to detect and differentiate Campylobacter fetus subspecies fetus and Campylobacter fetus subspecies venerealis

Bovine venereal campylobacter infection, caused by Campylobacter fetus venerealis, is of significant economic importance to the livestock industry. Unfortunately, the successful detection and discrimination of C. fetus venerealis from C. fetus fetus continue to be a limitation throughout the world. There are several publications warning of the problem with biotyping methods as well as with recent molecular based assays. In this study, assessed on 1071 isolates, we report on the successful development of two Real Time SYBR® Green PCR assays that will allow for the detection and discrimination of C. fetus fetus and C. fetus venerealis. The sensitivity reported here for the C. fetus (CampF4/R4) and the C. fetus venerealis (CampF7/R7) specific PCR assays are 100% and 98.7% respectively. The specificity for these same PCR assays are 99.6% and 99.8% respectively.     

Epidemiology and risk factors associated with Anaplasma marginale infection of cattle in Peninsular Malaysia

Bovine anaplasmosis is a major concern to cattle farming in most parts of the world. Anaplasmosis negatively impacts the profitability of cattle farming by reducing the production, reproduction, and draft ability of cattle. Here, we report results from a one-year cross sectional study to determine the epidemiology and the risk factors for Anaplasma marginale infection of cattle in Peninsular Malaysia. Examination of one thousand and forty five blood samples of apparently healthy cattle from forty-three farms in all the states of Peninsular Malaysia by polymerase chain reaction (PCR) assay revealed an overall prevalence of A. marginale infection of cattle of 72.6%, showing high endemicity of this heamoprotozoan among cattle in the country. Cattle breeds, production type, herd owner, herd size, management system, farm size, farm age, prophylactic treatment against blood parasites, presence of ticks, frequency of deticking, zones, closeness to forest, closeness to waste area, closeness to human settlement and closeness to body of water were the risk factors significantly associated (P?<?0.05) with the detection of A. marginale in cattle. Results of this first molecular study on the epidemiology and risk factors for A. marginale infection of cattle from all the states of Peninsular Malaysia suggest policies and strategies for the prevention and control of the parasite to improve profitability of cattle farming in the country.     

Sarcocystis in Muscles of Raccoons (Procyon lotor L.)1

Sarcocysts of Sarcocystis sp. were found in 26 (50%) of 52 raccoons (Procyon lotor) from Ohio, Pennsylvania, Florida, and Maryland. Although only 4 (7.7%) of 52 cardiac muscle specimens were found to contain sarcocysts, 25% to 36.5% of tongue, diaphragm, masseter muscle, and esophagus specimens were found infected. By light microscopy, sarcocyst walls were <3 μm thick and had no conspicuous projections; interior septa were indistinct. By transmission electron microscopy, sarcocyst walls had short (mean = 2.7 μm), villus-like protrusions; thin septa were seen within the sarcocysts. The raccoon may be an intermediate host for a Sarcocystis sp. that completes its life cycle in an unidentified, wild carnivore.     

Prevalence and Transmission of Trypanosoma cruzi in People of Rural Communities of the High Jungle of Northern Peru

BackgroundVector-borne transmission of Trypanosoma cruzi is seen exclusively in the Americas where an estimated 8 million people are infected with the parasite. Significant research in southern Peru has been conducted to understand T. cruzi infection and vector control, however, much less is known about the burden of infection and epidemiology in northern Peru.MethodologyA cross-sectional study was conducted to estimate the seroprevalence of T. cruzi infection in humans (n=611) and domestic animals [dogs (n=106) and guinea pigs (n=206)] in communities of Cutervo Province, Peru. Sampling and diagnostic strategies differed according to species. An entomological household study (n=208) was conducted to identify the triatomine burden and species composition, as well as the prevalence of T. cruzi in vectors. Electrocardiograms (EKG) were performed on a subset of participants (n=90 T. cruzi infected participants and 170 age and sex-matched controls). The seroprevalence of T. cruzi among humans, dogs, and guinea pigs was 14.9% (95% CI: 12.2 – 18.0%), 19.8% (95% CI: 12.7- 28.7%) and 3.3% (95% CI: 1.4 – 6.9%) respectively. In one community, the prevalence of T. cruzi infection was 17.2% (95% CI: 9.6 - 24.7%) among participants < 15 years, suggesting recent transmission. Increasing age, positive triatomines in a participant''s house, and ownership of a T. cruzi positive guinea pig were independent correlates of T. cruzi infection. Only one species of triatomine was found, Panstrongylus lignarius, formerly P. herreri. Approximately forty percent (39.9%, 95% CI: 33.2 - 46.9%) of surveyed households were infested with this vector and 14.9% (95% CI: 10.4 - 20.5%) had at least one triatomine positive for T. cruzi. The cardiac abnormality of right bundle branch block was rare, but only identified in seropositive individuals.ConclusionsOur research documents a substantial prevalence of T. cruzi infection in Cutervo and highlights a need for greater attention and vector control efforts in northern Peru.