Climate determines transmission hotspots of Polycystic Echinococcosis, a life-threatening zoonotic disease, across Pan-Amazonia.

Polycystic Echinococcosis (PE), a neglected life-threatening zoonotic disease caused by the cestode Echinococcus vogeli, is endemic in the Amazon. Despite being treatable, PE reaches a case fatality rate of around 29% due to late or missed diagnosis. PE is sustained in Pan-Amazonia by a complex sylvatic cycle. The hunting of its infected intermediate hosts (especially the lowland paca Cuniculus paca) enables the disease to further transmit to humans, when their viscera are improperly handled. In this study, we compiled a unique dataset of host occurrences (~86000 records) and disease infections (~400 cases) covering the entire Pan-Amazonia and employed different modeling and statistical tools to unveil the spatial distribution of PE's key animal hosts. Subsequently, we derived a set of ecological, environmental, climatic, and hunting covariates that potentially act as transmission risk factors and used them as predictors of two independent Maximum Entropy models, one for animal infections and one for human infections. Our findings indicate that temperature stability promotes the sylvatic circulation of the disease. Additionally, we show how El Niño-Southern Oscillation (ENSO) extreme events disrupt hunting patterns throughout Pan-Amazonia, ultimately affecting the probability of spillover. In a scenario where climate extremes are projected to intensify, climate change at regional level appears to be indirectly driving the spillover of E. vogeli. These results hold substantial implications for a wide range of zoonoses acquired at the wildlife-human interface for which transmission is related to the manipulation and consumption of wild meat, underscoring the pressing need for enhanced awareness and intervention strategies.

Molecular characterization of Sarcoptes scabiei causing severe mange in two Andean foxes (Lycalopex culpaeus) from Peru.

Cases of sarcoptic mange in the wildlife population have been increasing around the world in recent years. In this study, we report the first case of severe sarcoptic mange in two Andean foxes (Lycalopex culpaeus) and molecularly analyze the collected mites. The National Forestry and Wildlife Service of Lima, Peru, found an adult male Andean fox in the province of Callao in August 2022. The veterinarians decided to euthanize the fox due to the severity of the mange. In August 2023, an adult male Andean fox was found dead in the province of Huaral by veterinarians. Both foxes were sent to the veterinary school in Lima for necropsy. Skin samples from different body zones were digested in buffer lysis, and mites were detected in the tissue samples. A morphological diagnosis identified the mites as Sarcoptes scabiei. The mites from both foxes had the same nuclear (ITS2) and mitochondrial (cox1) genetic marker sequences as the S. scabiei sequences from dogs, vicunas, Andean foxes, and water buffalos recorded in GenBank. Unlike ITS2, phylogenetic analysis of S. scabiei cox1 showed host-related nucleotide sequence polymorphisms. Future molecular studies of S. scabiei from different hosts and localities will be necessary to better understand the transmission of this disease in Andean foxes.

Identification of wild rodents as intermediate hosts for Hydatigera taeniaeformis in Peru.

Hydatigera taeniaeformis is a cestode that uses felines and rodents as definitive and intermediate hosts, respectively. Its larval stage, or metacestode, infects a wide variety of rodent species and develops in the liver parenchyma into a cyst. The aim of this study was to evaluate the occurrence of H. taeniaeformis metacestode in various species of wild rodents from Peru. For this, the livers of 356 rodents were macroscopically examined for any parasitic form compatible with metacestodes. Metacestodes were identified by measuring characteristic morphological parameters, and the diagnosis was confirmed by molecular analysis of a fragment of the cytochrome c oxidase subunit 1 gene (cox1). Five rodents: two small-eared pygmy rice rats (Oligoryzomys microtis), two white-naped squirrels (Simosciurus nebouxii), and one pygmy rice rat (Oligoryzomys sp.) were infected with H. taeniaeformis metacestodes. The cox1 sequences from our metacestodes showed up to 100% identity with previous H. taeniaeformis sequences from the GenBank. These results demonstrated the occurrence of H. taeniaeformis in new intermediate hosts, as well as the first molecular contribution for H. taeniaeformis from Peru.

Prevalence and molecular characterization of Sarcoptes scabiei from vicuñas (Vicugna vicugna) from Southern Peruvian Andes.

Sarcoptic mange is a disease caused by an infectious parasite in the vicuñas (Vicugna vicugna) from South America. Although molecular studies have provided much information about the epidemiology of this disease, this information is still unknown in vicuñas. This study determined the prevalence and molecular characterization of Sarcoptes scabiei from vicuñas from Southern Peruvian Andes. During the 2018 shearing season, 181 vicuñas were clinically evaluated for lesions compatible with mange. Sarcoptes scabiei was detected in 35 (19.3%) vicuñas, and 50 mites from 25 vicuñas were selected for molecular analyses of the mitochondrial (cox1) and nuclear (ITS2) genetic markers. Molecular analyses of the cox1 and ITS2 sequences showed an identity of 94­99% and 99.8­100% with previous S. scabiei sequences registered in the GenBank, respectively. Sequence polymorphisms were more evident in the ITS2 than in the cox1, but only the cox1 had an association with the host. Phylogenetic analysis of S. scabiei cox1 sequences from vicuñas showed a cluster with S. scabiei cox1 sequences from canids, suggesting that the origin of S. scabiei from vicuña is associated with canid mites. This research is the first molecular analysis of S. scabiei from vicuñas. Future molecular studies will be necessary to determine the species variety, geographic segregation and host­parasite adaptation for this vicuña's mite.

Cryptosporidium parvum as a risk factor of diarrhea occurrence in neonatal alpacas in Peru.

Cryptosporidiosis has been reported as an important cause of neonatal diarrhea and mortality in cattle, sheep, and other ruminants, but its impact on alpaca health has not been studied thoroughly. In this study, we have determined the prevalence and evaluated the role of cryptosporidiosis as a risk factor for diarrhea occurrence in newborn alpacas. During the calving season (January-March) of 2006, stool specimens (N = 1312) were collected from 24 herds of newborn alpacas in Puno and Cuzco, departments that account for the largest populations of alpacas in Peru. All the specimens were microscopically screened for Cryptosporidium spp. using the acid-fast technique. The association between Cryptosporidium detection and diarrhea was analyzed using χ2 test and generalized lineal model. Cryptosporidium species were determined by PCR-RFLP analysis of the small subunit rRNA gene. Cryptosporidium oocysts were detected in 159 of 1312 (12.4%) newborn alpacas. Results of the analyses demonstrated that crypstosporidiosis was significantly associated with diarrhea (PR = 3.84; CI95% 2.54-5.81; p < 0.0001). Only Cryptosporidium parvum was detected in the 153 Cryptosporidium-infected animals. Thus, there is an association of C. parvum infection with diarrhea in neonatal alpacas.

Correction to: Molecular characterization of the Taenia solium Tso31 antigen and homologous of other Taenia species from Peru.

The original version of this article contained a mistake.

Molecular characterization of the Taenia solium Tso31 antigen and homologous of other Taenia species from Peru.

Several studies have been performed to determine specific antigens for the diagnosis of tapeworms. One of these antigens is Tso31, which is used to differentiate Taenia solium and Taenia saginata in human feces. The aim of the present work was the molecular characterization of this protein in different tapeworm specimens collected in Peru: T. omisa (n = 6), T. hydatigena (n = 7), T. taeniaeformis (n = 4), T. pisiformes (n = 1), T. multiceps (n = 7), and T. solium (n = 10). Total DNA was extracted from each proglottid using a commercial DNA kit for tissue. A nested PCR was used to amplify a fragment of the previously described oncosphere-specific protein Tso31 gene. The nested PCR products were analyzed by 1.5% agarose gel electrophoresis and visualized after ethidium bromide staining. All nested PCR-positive products were sequenced and their sequences were compared. Of all the tapeworms analyzed, only T. solium and T. multiceps amplified the Tso31 gene. All sequences were identical for each species. Our T. solium Tso31 showed 100% similarity when compared with published GenBank sequences. The difference between T. solium and T. multiceps Tso31 samples was 8.1%. In conclusion, our results show that the tsol31 gene is not exclusive to T. solium.

Polycystic echinococcosis in Pacas, Amazon region, Peru.

In the Peruvian Amazon, paca meat is consumed by humans. To determine human risk for polycystic echinococcosis, we examined wild pacas from 2 villages; 15 (11.7%) of 128 were infected with Echinococcus vogeli tapeworms. High E. vogeli prevalence among pacas indicates potential risk for humans living in E. vogeli-contaminated areas.

The vicuna (Vicugna vicugna) as a natural host of Dictyocaulus filaria in Peru.

Lungworm infection, or verminous pneumonia, is a parasitic disease that causes serious problems in small and large ruminants. Despite the fact that nematodes of the genus Dictyocaulus in cattle and sheep are the main cause of this disease, there are few studies on the natural infections of South American camelids. For this reason, this study aims to report the natural infection by Dictyocaulus filaria in vicunas (Vicugna vicugna) for the first time. During a shearing season (chaku) in Cuzco, Peru, two accidentally killed adult vicunas were submitted to the IVITA-Marangani research center in Cuzco for their respective necropsies. The tracheas of both vicunas had numerous nematodes, as seen during the necropsy. The nematodes were collected in 70% ethanol and were morphologically identified as D. filaria. Likewise, the DNA of six nematodes was extracted, and the ITS2 region and the 28S rRNA gene were amplified and sequenced. The nucleotide sequences of both genetic markers were up to 100% identical with previously reported D. filaria DNA sequences found in the goat yearlings from Turkey, sheep from Iran, Turkey, and India, and the argali from Uzbekistan, which confirmed the morphological diagnosis. This finding represents the first molecular confirmation of a natural D. filaria infection in a South American camelid. It will be necessary to carry out future studies to know the current situation of verminous pneumonia in domestic and wild South American camelids and to know the negative effects of the disease on them.

Circadian rhythm of salivary and serum urea concentration in alpacas and sheep receiving diets with different levels of protein.

All vertebrates possess a daily rhythm, encompassing a comprehensive set of physiological, cognitive, and behavioral patterns that manifest throughout a 24-hour period. The aim of this study was to compare the effect of crude protein (CP) levels in the diet on the daily rhythm of urea in serum (US) and saliva in alpacas and sheep. Ten alpacas and ten sheep, adult, clinically healthy males, were used; they were maintained in natural light conditions and fed ad libitum with two levels of CP (16 and 7%). Blood and saliva samples were taken every 4 h for 48 h. A two-way ANOVA was conducted to analyze the parameters, including adjusted mean rhythm (MESOR), amplitude, and acrophase. It was found that both US and saliva urea exhibited circadian rhythms with a peak during the midday (10:59 - 12:16 h). The MESOR with low CP diets was higher (P < 0.05) in alpacas. The MESOR of urea levels in saliva was greater (P < 0.05) at the highest level of CP in the diet, with no differences between alpacas and sheep (P > 0.05). The amplitude was greater (P < 0.05) in alpacas and at the high level of CP compared to the low level of CP in the diet. Our findings reveal that both serum and saliva urea levels in alpacas and sheep follow a daily rhythm and the MESOR of US was higher in alpacas when they consume food with low CP content, and this difference disappears when CP levels are increased in the diet.

Molecular survey of hemoplasmas in asymptomatic vicunas (Vicugna vicugna) from the Pampa Galeras Bárbara D'Achille National Reserve in Peru.

Hemotrophic mycoplasmas (hemoplasmas) are epierythrocytic bacteria that infect wild and domestic animals, and can cause anemia in some of them. They are considered emerging and zoonotic pathogens, causing serious health problems in wildlife. Candidatus Mycoplasma haemolamae is the only species of hemoplasma that infects domestic South American camelids (alpacas and llamas), with limited studies in wild camelids. Therefore, the objective of this study was to determine the prevalence of Candidatus M. haemolamae in vicunas (Vicugna vicugna) from the Pampa Galeras National Reserve, located in the Ayacucho region of Peru, using molecular diagnosis. For this, blood samples from 79 vicunas were collected, which were molecularly analyzed by partially amplifying the 16S ribosomal RNA gene of Mycoplasma sp. Fourteen vicunas (17.7 %) were positive for the molecular diagnosis of Mycoplasma sp. All PCR-positive products were sequenced and showed more than 99 % identity with Candidatus M. haemolamae. Statistical analysis showed that tick-infested vicunas had 6.10 odds of presenting Candidatus M. haemolamae compared with tick-free vicunas. Sex and age were not associated with Candidatus M. haemolamae infections. This is the first report of hemoplasmas in vicunas, a wild South American camelid, demonstrating that the pathogen can have both a domestic and a wild life cycle. Future studies are necessary to know the current situation of this pathogen in domestic and wild camelids from other locations in Peru.

Seroprevalence of Toxoplasma gondii, risk factors and knowledge about toxoplasmosis in undergraduate students from Lima, Peru.

Toxoplasma gondii is the causative agent of toxoplasmosis, a zoonotic disease of worldwide distribution. The aim of this study was to assess the seroprevalence of T. gondii in undergraduate students from Lima, Peru, and to identify the risk factors linked to the infection. For this, serum samples of 100 undergraduate students of the Faculty of Biological Sciences were tested for T. gondii antibodies with a commercially available ELISA. The seroprevalence of T. gondii in these subjects was 7 %. Only the age of students showed a statistical association with T. gondii seropositivity. The level of awareness regarding toxoplasmosis was also investigated. In the sample, 71 % of the students are aware of toxoplasmosis and 64 % that a parasite is the cause of the infection. Most know it is transmitted through undercooked meat (57 %), but are unaware of contaminated vegetables (40 %), organ transplants (17 %), blood transfusions (32 %), and soil contact (39 %). In the epidemiological context it will be valuable to verify toxoplasmosis awareness in other population groups and other regions in Peru.

Molecular detection of Toxoplasma gondii in domestic and wild guinea pigs (Cavia spp.) from the Marangani district in Cuzco, Peru.

Toxoplasmosis is a foodborne disease caused by the protozoan Toxoplasma gondii, and transmitted to humans by eating raw or undercooked meat, mainly. Poultry, beef, and pork are the main meats consumed in Peru; despite this, guinea pig meat is also widely consumed. For this reason, the objective of this study was to molecularly detect T. gondii in domestic and wild guinea pigs from the Marangani district in Cuzco, Peru, and identify some risk factors associated with this pathogen. DNA was extracted from the brain tissue samples of guinea pigs (30 domestic and 30 wild), and PCR protocols were used to amplify the internal transcribed spacer (ITS-1) region and a 529 bp fragment from the T. gondii genome. T. gondii DNA was detected in 14 (23.3%) guinea pigs. T. gondii frequency was 33.3% in domestic guinea pigs and 13.3% in wild guinea pigs. Our results demonstrated that guinea pigs represent an important source for T. gondii infection in human populations in this locality.

Concordance between two monoclonal antibody-based antigen detection enzyme-linked immunosorbent assays for measuring cysticercal antigen levels in sera from pigs experimentally infected with Taenia solium and Taenia hydatigena.

BACKGROUND: Antigen detection in Taenia solium cysticercosis confirms viable infection in the intermediate host (either pig or human). The reference B158/B60 monoclonal antibody (mAb)-based Ag-enzyme-linked immunosorbent assay (ELISA) has acceptable levels of sensitivity and specificity in human neurocysticercosis with multiple brain cysts, although its sensitivity is lower in cases with single brain cysts, whereas in porcine cysticercosis the assay specificity is affected by its frequent cross-reaction with Taenia hydatigena, another common cestode found in pigs. Our group has produced 21 anti-T. solium mAbs reacting against antigens of the whole cyst, vesicular fluid, and secretory/excretory products, identifying TsW8/TsW5 as the most promising pair of mAbs for an Ag-ELISA. METHODS: We report the use of the TsW8/TsW5 Ag-ELISA to measure cysticercus antigen levels [expressed as optical density (OD) values] in two panels of sera collected from day 0 (baseline) to day 90 postinfection (PI) from pigs experimentally infected with T. solium (n = 26) and T. hydatigena (n = 12). At baseline and on days 28 and 90 PI, we used Bland-Altman (BA) analysis and Lin's concordance correlation coefficients (CCC) to determine the concordance between the TsW8/TsW5 and the B158/B60 Ag-ELISA. RESULTS: The TsW8/TsW5 Ag-ELISA was able to efficiently measure circulating antigen levels in T. solium-infected pigs, similar to that obtained with the B158/B60 Ag-ELISA. Almost all paired log-OD differences between assays were within the limits of agreement (LoA) in the BA analysis at baseline and on days 28 and 90 PI (92.3%, 100%, and 100%, respectively), and a high concordance of log-ODs between assays was also found (Lin's CCC: 0.69, 0.92, and 0.96, respectively, all P < 0.001). In pigs infected with T. hydatigena, almost all paired log-OD differences were within the LoA in the BA analysis, whereas the concordance of log-ODs between assays was low at baseline (Lin's CCC: 0.24) but increased on days 28 and 90 PI (Lins' CCC: 0.88 and 0.98, P < 0.001). CONCLUSIONS/SIGNIFICANCE: The TsW8/TsW5 Ag-ELISA recognizes antigens in pigs with T. solium cysticercosis and is highly concordant with the B158/B60 Ag-ELISA. However, its diagnostic use is hampered by cross-reactions with T. hydatigena, as in other mAb-based Ag-ELISAs.

Antibody Banding Patterns on the Enzyme-Linked Immunoelectrotransfer Blot (EITB) Assay Clearly Discriminate Viable Cysticercosis in Naturally Infected Pigs.

Enzyme-linked immunoelectrotransfer blot (EITB) detects antibodies against seven Taenia solium larvae antigens in three protein families (GP50, T24/42, and 8-kDa) with different structures and functions. EITB banding patterns against these antigens in pigs provide information about the course of infection and may discriminate viable cysticercosis. We analyzed the banding patterns and infection outcomes (presence of viable cysts, degenerated cysts, and any cysts) of 512 rural pigs. Banding patterns were grouped into homogenous classes using latent class analysis, and relationships with infection outcomes were assessed. Four classes were identified: 1 (n = 308, EITB-negative or positive for the GP50 family), 2 (n = 127, positive for GP50 (GP50 family), GP42-39 and GP24 (T24/42 family), but negative for 8-kDa antigens), 3 (n = 22, positive for GP50 and T24/42 antigens (GP42-39 and GP24), as well as to 8-kDa bands GP13, GP14, and GP18, but negative for GP21), and 4 (n = 55, positive for GP50 and T24/42 antigens, as well as to 8-kDa antigens GP21 and GP18 in combination). Pigs in classes 3 and 4 were more likely to have viable cysts (72.6% and 96.4%, respectively) than pigs in classes 1 and 2 (0.7% and 27.6%, respectively; p < 0.001). The number of infections with any cysts was higher in classes 3 and 4 (77.3% and 98.2%, respectively) and lower in classes 2 and 1 (34.7% and 4.9%, respectively; p < 0.001). Pigs with viable cysts represented >90% of pigs with any cysts in classes 3 and 4 (94.1% and 98.2%, respectively), while degenerated cysts were frequent among pigs with any cysts in classes 1, 3, and 2 (86.7%, 47.1%, and 43.2%, respectively; p < 0.001). EITB banding patterns strongly correlate with cysticercosis infection status in rural pigs, with classes 3 and 4 being more predictive of viable infections.

Extended outbreak of cryptosporidiosis in a pediatric hospital, China.

Four Cryptosporidium spp. and 6 C. hominis subtypes were isolated from 102 of 6,284 patients in 3 pediatric hospitals in People's Republic of China. A cryptosporidiosis outbreak was identified retrospectively. The outbreak lasted >1 year and affected 51.4% of patients in 1 hospital ward, where 2 C. hominis subtypes with different virulence were found.

Cotylophoron panamensis (Trematoda: Paramphistomidae) in Mazama americana (Artiodactyla: Cervidae) free-living in remote areas in the Peruvian Amazon.

Trematodes of the genus Cotylophoron cause mucosal lesions in pre-stomachs and in small intestine in cattle, generating losses in animal production. In the Northeastern Peruvian Amazon, the presence of Cotylophoron panamensis in the 16.7% (4/24) in free-living red brocket deers (Mazama americana) in areas distant from livestock farming suggests the red brocket is a natural wild host of C. panamensis.

Seroprevalence of Toxoplasma gondii and associated risk factors in cats from Lima, Peru.

Toxoplasmosis is an important zoonotic disease worldwide caused by the intracellular parasite Toxoplasma gondii. Cats, being hosts, act as a good sentinel for this disease. Thus, the objective of this study was to determine the seroprevalence of T. gondii in cats by examining serum from seven districts of Metropolitan Lima, Peru. We collected and analyzed 303 cat serum samples, and the owners answered a questionnaire about age, gender, lifestyle (indoors only and outdoors access) and feeding (commercial and home food). The samples were tested using indirect hemagglutination (IHA) for detection of antibody IgM and IgG. Among the animals analyzed, we found 52 (17.2%, 95% CI: 13.1% - 21.9%) seropositive cats to T. gondii, of which one corresponded to acute infection (IgM) and 51 to chronic infections (IgG). In addition, the presence of anti-T. gondii antibodies was associated with feeding commercial food and living outdoors access. Our results concluded that T. gondii infections are common in cats with owners in Metropolitan Lima and will be useful to future epidemiological studies.

Echinococcus granulosus sensu stricto and E. canadensis are distributed in livestock of highly endemic area in the Peruvian highlands.

The prevalence of cystic echinococcosis is high in many livestock areas of Peru, where intermediate hosts such as sheep, cattle, and South American camelids can be infected. Several species of E. granulosus have been described in relation to its genetic diversity and distribution. The aim of this study was to determine the species of E. granulosus sensu lato (s.l.) metacestodes collected from sheep, cattle, swine and camelids at different localities in the department of Puno, in the southern highlands of Peru. One hundred and fifty-two echinococcal cysts were collected from 10 different locations. E. granulosus s.l. species were determined by amplification of the Internal transcribed spacer 1 of the ribosomal DNA using a Nested PCR-RFLP technique. The cytochrome C oxidase 1 gene (450 bp) was also amplified and sequenced in samples with different RFLP patterns. Cysts samples were collected from sheep (39.5%), cattle (32.9%), pigs (15.8%) and alpacas/llamas (11.8%). E. granulosus sensu stricto (G1 genotype) was mainly identified in all animal hosts, while, the E. canadensis (G7) was only identified in cysts from pigs and alpacas. This is the first report of E. granulosus sensu stricto and E. canadensis in llamas and alpacas, respectively. Knowledge of species and molecular epidemiology of E. granulosus s.l. in endemic areas in Peru may help to evaluate preventive programs, understand disease transmission, as well as improve vaccine and chemotherapy effectiveness.

Development of a dose-response model for porcine cysticercosis.

Taenia solium is an important cause of acquired epilepsy worldwide and remains endemic in Asia, Africa, and Latin America. Transmission of this parasite is still poorly understood despite the design of infection experiments to improve our knowledge of the disease, with estimates for critical epidemiological parameters, such as the probability of human-to-pig infection after exposure to eggs, still lacking. In this paper, a systematic review was carried out and eight pig infection experiments were analyzed to describe the probability of developing cysts. These experiments included different pathways of inoculation: with ingestion of proglottids, eggs, and beetles that ingested eggs, and direct injection of activated oncospheres into the carotid artery. In these experiments, different infective doses were used, and the numbers of viable and degenerated cysts in the body and brain of each pig were registered. Five alternative dose-response models (exponential, logistic, log-logistic, and exact and approximate beta-Poisson) were assessed for their accuracy in describing the observed probabilities of cyst development as a function of the inoculation dose. Dose-response models were developed separately for the presence of three types of cysts (any, viable only, and cysts in the brain) and considered for each of the four inoculation methods ("Proglottids", "Eggs", "Beetles" and "Carotid"). The exact beta-Poisson model best fit the data for the three types of cysts and all relevant exposure pathways. However, observations for some exposure pathways were too scarce to reliably define a dose-response curve with any model. A wide enough range of doses and sufficient sample sizes was only found for the "Eggs" pathway and a merged "Oral" pathway combining the "Proglottids", "Eggs" and "Beetles" pathways. Estimated parameter values from this model suggest that a low infective dose is sufficient to result in a 50% probability for the development of any cyst or for viable cyst infections. Although this is a preliminary model reliant on a limited dataset, the parameters described in this manuscript should contribute to the design of future experimental infections related to T. solium transmission, as well as the parameterization of simulation models of transmission aimed at informing control.