Protozoal Agents Research Articles

Structural bases that underline Trypanosoma cruzi calreticulin proinfective, antiangiogenic and antitumor properties.

Microbes have developed mechanisms to resist the host immune defenses and some elicit antitumor immune responses. About 6 million people are infected with Trypanosoma cruzi, the protozoan agent of Chagas' disease, the sixth neglected tropical disease worldwide. Eighty years ago, G. Roskin and N. Klyuyeva proposed that T. cruzi infection mediates an anti-cancer activity. This observation has been reproduced by several other laboratories, but no molecular basis has been proposed. We have shown that the highly pleiotropic chaperone calreticulin (TcCalr, formerly known as TcCRT), translocates from the parasite ER to the exterior, where it mediates infection. Similar to its human counterpart HuCALR (formerly known as HuCRT), TcCalr inhibits C1 in its capacity to initiate the classical pathway of complement activation. We have also proposed that TcCalr inhibits angiogenesis and it is a likely mediator of antitumor effects. We have generated several in silico structural TcCalr models to delimit a peptide (VC-TcCalr) at the TcCalr N-domain. Chemically synthesized VC-TcCalr did bind to C1q and was anti-angiogenic in Gallus gallus chorioallantoic membrane assays. These properties were associated with structural features, as determined in silico. VC-TcCalr, a strong dipole, interacts with charged proteins such as collagen-like tails and scavenger receptors. Comparatively, HuCALR has less polarity and spatial stability, probably due to at least substitutions of Gln for Gly, Arg for Lys, Arg for Asp and Ser for Arg that hinder protein-protein interactions. These differences can explain, at least in part, how TcCalr inhibits the complement activation pathway and has higher efficiency as an antiangiogenic and antitumor agent than HuCALR.

Lineage-specific rapid diagnostic tests can resolve Trypanosoma cruzi TcII/V/VI ecological and epidemiological associations in the Argentine Chaco

BackgroundTrypanosoma cruzi, the protozoan agent of Chagas disease, is comprised of at least 6 genetic lineages (TcI-TcVI). Their geographical distribution, clinical associations and reservoir hosts are not fully elucidated, as genotyping is hampered due to the difficulty in isolating representative populations of organisms. Lineage-specific serological techniques may address these issues.MethodsTrypanosoma cruzi lineage-specific serological assays were performed on human, canine, feline and armadillo sera from the Gran Chaco in northern Argentina, a region of ongoing transmission. Synthetic peptides representing lineage-specific epitopes of the trypomastigote small surface antigen (TSSA) were used in ELISA, and the TcII/V/VI shared epitope peptide (TSSApep-II/V/VI) was used in the Chagas Sero K-SeT rapid diagnostic test (RDT).ResultsChagas Sero K-SeT RDT, using Protein G to detect human and canine IgG, was at least as sensitive as TSSApep-II/V/VI ELISA using specific secondary antibodies. For sera from humans TSSApep-II/V/VI seroprevalence by Chagas Sero K-SeT was 273/393 (69.5%), for dogs 48/73 (65.8%) and for armadillos 1/7 (14.3%); by ELISA for cats 5/19 (26.3%). The seroprevalence for humans was similar to that for Bolivian patients, amongst whom we previously observed an association of TSSApep-II/V/VI seropositivity with severity of cardiomyopathy. In humans, prevalence of TSSApep-II/V/VI recognition was associated with locality, and with increasing and decreasing age within the Qom and Creole populations, respectively. For dogs TSSApep-II/V/VI recognition was associated with being born before community-wide insecticide spraying (P = 0.05) and with Qom household (P < 0.001).ConclusionsWe show here that Chagas Sero K-SeT RDT can replace ELISA for TSSApep-II/V/VI serology of humans and dogs; for humans there were statistically significant associations between a positive Chagas Sero K-SeT RDT and being resident in Area IV, and for dogs association with Qom household or with being born before the mass spraying campaign; we also show that with cats the TcII/V/VI epitope can be detected by ELISA. We assessed the lineage distribution in an unprecedented 83% of the human T. cruzi-seropositive population. These results form the basis for more detailed studies, enabling rapid in-the-field surveillance of the distribution and clustering of these lineages among humans and mammalian reservoirs of T. cruzi infection.

Serological and Molecular Findings of Leishmania Infection in Healthy Donkeys (Equus asinus) from a Canine Leishmaniosis Endemic Focus in Tuscany, Italy: A Preliminary Report.

Leishmania parasites are considered to be emergent zoonotic pathogens, which is a new concept regarding their epidemiology and the identification of novel animal hosts. The present study is the first in Italy to evaluate anti Leishmania seroprevalence, and the first in Europe to detect parasite DNA in donkeys’ blood. The study was performed on jennies living in a Leishmania infantum endemic area of Central Italy. One hundred and ten blood samples were obtained from 67 healthy lactating Amiatina jennies that were semi-extensively reared in Tuscany. When possible, more than one sample was subsequently obtained from the same subject. All samples were processed by immunofluorescence antibody test (IFAT) and by polymerase chain reaction (PCR). For the results, 11 out of 30 animals (36.7%) showed positive scores under IFAT. In addition, 22 out of the other 37 jennies had positive scores, also. The animals showed titers ranging from 40 to 320. Furthermore, 2 subjects that were submitted for 2 and 3 blood samplings, both had more than one positive score. Moreover, 2 seropositive animals were positive for Leishmania DNA. Donkeys are considered to be a preferred source for a sandfly blood meal, even if clinical leishmaniosis has never been reported in Europe for this animal species. In the view of these facts, our preliminary findings would suggest the role of donkey as a potential reservoir for this protozoan agent. Additional studies would be welcome to elucidate the role of the donkey in Leishmania epidemiology of CanL endemic areas and to confirm the preliminary findings and the hypothesis proposed here.

Metabolic Labeling of Surface Neo-sialylglyconjugates Catalyzed by Trypanosoma cruzi trans-Sialidase.

Trypanosoma cruzi, the protozoan agent of Chagas disease, has evolved an innovative metabolic pathway by which protective sialic acid (SA) residues are scavenged from host sialylglycoconjugates and transferred onto parasite surface mucin-like molecules (or surface glycoconjugates from host target cells) by means of a unique trans-sialidase (TS) enzyme. TS-induced changes in the glycoprotein sialylation profile of both parasite and host cells are crucial for the establishment of a persistent T. cruzi infection and for the development of Chagas disease-associated pathogenesis. In this chapter, we describe a novel metabolic labeling method developed in our labs that enables straightforward identification and molecular characterization of SA acceptors of the TS-catalyzed reaction.

Prevalence of Toxoplasma gondii infections in swine of non-tecnified rearing farms of the northeastern region of the state of São Paulo, Brazil and associated risk factors

Toxoplasmosis is a zoonosis present worldwide. Its protozoal aethiological agent, Toxoplasma gondii, has the ability to infect several homeothermic animals and mainly human beings. The consumption of raw or undercooked meat products containing T. gondii cysts, consumption of vegetables without washing and using non-treated water are risk factors associated to the occurrence of human toxoplasmosis. Furthermore, raw or undercooked pork is an important infection source of T. gondii to humans. Due to the importance of toxoplamosis in public health, this study focused on establish the prevalence of the disease in non-technified swine herds in the northeastern region of the State of São Paulo, Brazil, using Modified Agglutination Test (MAT) and the Indirect Immunofluorescence Assay (IFA) and the risk factors for its occurrence. In addition, the agreement among both diagnostic tests was evaluated. A low prevalence of toxoplasmosis was found at animal level (7.02%). The Fisher's exact test detected correlation between positive cases with the presence of food garden in the farm (p = 0.01) and the use of non-treated water to irrigate the food garden (p = 0.005). The agreement among tests was considered moderate (Kappa index = 0.5). The results show that toxoplasmosis is a risk for humans who consume under cooked pork meat in this region and an acceptable agreement between MAT and IFA tests.

A review of some tick-borne pathogens of dogs

Ticks and tick-borne diseases have great economic and medical importance worldwide and they affect both animal and human health by sucking blood and also transmitting protozoan, bacterial, rickettsial, spirochetal and viral agents. Ticks can live in all regions of the world except Polar Regions. Tick-borne encephalitis Virus, Babesiosis, Anaplasmosis, Ehrlichiosis, and Hepatozoonosis are important tick-borne diseases of dogs and they influence a great variety of other domestic and wild animals. Ticks are ectoparasites of mammals, birds and reptiles specializing as obligate blood sucking permanent ectoparasitic arthropods. As vector of important haemoparasitic disease, tick surpasses all other arthropods, apart from mosquitoes as diseases agents of humans and lead to poor performance of the animals. One or more of the approximately 840 known species of ticks are found in most terrestrial regions of the earth. Two major families of ticks are ixodidae (hard bodies ticks) and argasidae (soft bodies ticks), with ixodidae being the largest and most important family. These vectors such as Rhipicephalus sanguineus and Ixodes ricinus which are endemic in Nigeria, have affected the performance of dogs which are major human companions through their activities such as blood sucking, disease transmission, biting effect and causing listlessness through itching and scratching. The important pathogens dealt with in this study, include tick-borne encephalitis virus, Ehrlicia canis, Anaplasma phagocytophilum, Hepatozoon canis and Babesia canis. This review aims at to create better awareness on ticks and tick-borne pathogens of dogs providing latest knowledge on prevention and control of this menace.

Bionomics of phlebotomine sand flies species (Diptera: Psychodidae) and their natural infection with Leishmania and Crithidia in Fars province, southern Iran.

Phlebotominae sand flies are involved in human diseases, such as leishmaniasis, and cause a considerable number of deaths every year. Besides, some of them have been identified as allergen sources or the potential mechanical vectors related to nosocomial infections. The present study aimed to assess the monthly activity, fauna, and detection of protozoan agents in phlebotomine sand flies using polymerase chain reaction (PCR) in re-emerging zoonotic cutaneous leishmaniasis foci of Shiraz and Kharameh in Fars province, southern Iran during 2016-2017. To determine the monthly activity, sand flies were caught from indoors and outdoors of both studied areas. Afterward, all female phlebotomine sand flies were processed for DNA extraction and PCR assays for Leishmania and Crithidia detections. During the study, 6975 sand flies of 16 species (eight Phlebotomus and eight Sergentomyia species) were caught in both foci. Sand flies' monthly activities started in early April and terminated in late November and October. Additionally, two active peaks of sand flies were observed in both foci; first in June and second in August to September. Phlebotomus papatasi (47.1%) was the most dominant species in out/indoors of both Shiraz (31.1%) and Kharameh (16.0%). It was also the only species which was found infected with Leishmania major, indeed, 2.68% and 2.53% of P. papatasi were infected to L. major in Kharameh and Shiraz, respectively. However, none of the female sand flies was positive for Crithidia spp. Despite various control strategies, especially against Leishmania, considerable cases of leishmaniasis are recorded from Iran every year. Phlebotomine plays the main role in transmission of Leishmania in these foci. Therefore, further studies are needed to determine the role of different phlebotomine species in epidemiological aspects of leishmaniasis.

Occurrence of selected viral, bacterial and protozoan pathogens in fresh juices and smoothies in Prague, Czech Republic

Fresh squeezed juices and smoothies currently enjoy great popularity among consumers. However, data regarding the microbiological safety of these products sold to the public in food outlets are either very limited or missing completely. Within the current study, 80 samples of fresh juices and smoothies collected from food outlets in Prague, Czech Republic, were examined using culture and molecular methods for the presence of selected viral, bacterial and protozoan agents. One fifth of the smoothies and juices collected at food outlets contained Staphylococcus aureus, Yersinia enterocolitica, Cryptosporidium sp. or Giardia lamblia. The number of pathogens in all samples was lower than 50 CFU/g or 10 genome equivalents/g; in most cases pre-enrichment was required for successful culture of bacteria. Mycobacteria, human noroviruses (NoV GI and NoV GII) and adenoviruses were not detected at all. Smoothies and fresh juices are consumed without any further (thermal) treatment. Thus, the presence of pathogenic agents could have a significant impact on consumer health.

Molecular detection of Anaplasma bovis, Ehrlichia canis and Hepatozoon felis in cats from Luanda, Angola

BackgroundMolecular identification of tick-borne pathogen infection in cats from Africa is scarce. The presence of bacterial (Anaplasma and Ehrlichia) and protozoal (Babesia and Hepatozoon) agents was investigated in blood samples from 102 domestic cats from Luanda, Angola, by polymerase chain reaction and DNA sequencing.ResultsThree cats (2.9%) were found infected with Ehrlichia canis, three (2.9%) with Hepatozoon felis and one (1.0%) with Anaplasma bovis. The prevalence of infections with one single agent was 4.9%, and that of infection with two agents (i.e. E. canis and H. felis) was 1.0%. In total, six cats (5.9%) were found infected with at least one of the detected tick-borne agents.ConclusionsThis is the first report of A. bovis, E. canis and H. felis in cats from Angola. To the best of our knowledge, A. bovis is also being reported for the first time in domestic cats outside of Japan. Cats are at a low to moderate risk of being infected with tick-borne agents in Luanda.

Detection rates of waterborne protozoa in water sources from Fayoum Governorate

Background: Waterborne protozoal infections are common health problems in many parts of the world especially in developing countries. Water is a major vehicle for transmission of protozoa such as G. lamblia, Cryptosporidium spp. as well as pathogenic and opportunistic free living amoeba (FLA).Objective: This study aims to detect the presence of protozoal agents in tap water and storage water tanks at Fayoum Governorate, Egypt.Material and Methods: A total of ninety five water samples were collected from different water sources, taps (65) and tanks (30), from 6 Fayoum districts. The samples were processed to detect the presence of G. lamblia cysts by Lugol’s iodine stain, Cryptosporidium oocysts by modified Ziehl-Neelsen stain and FLA by cultivation. After cultivation, Acanthamoeba spp. were identified according to their morphological features and flagellation test was performed to detect amoeboflagellates.Results: All water samples collected from tanks (100%) were contaminated by protozoa of medical importance, while only 6 (9.2%) of the tap water samples were pathogen free. The majority of water samples were contaminated with mixed protozoal infections. The overall detection rates of contaminants in water sources were 86.3%, 52.6%, 13.7% by FLA, Cryptosporidium spp. and G. lamblia, respectively.Conclusions: The recorded detection rates of waterborne protozoa present a hazard to the community resulting in silent morbidities and mortalities. It is strongly recommended to adopt proper water safety measures.

Extended Screening Costs Associated With Selecting Donors for Fecal Microbiota Transplantation for Treatment of Metabolic Syndrome-Associated Diseases

BackgroundKnowledge of the impact of the gut microbiome on conditions other than Clostridium difficile infection has been rapidly increasing, and the potential usefulness of fecal microbiota transplantation (FMT) in these indications is being explored. The need to exclude donors with an increased risk of these diseases has left uncertainties regarding the cost and feasibility of donor screening. The aim of this study was to compare our experience to other donor-screening programs and report the costs associated with establishing a donor-screening program, for the treatment of metabolic syndrome-related conditions.MethodsForty-six potential donors (PDs) had their medical histories and physical examinations undertaken by a physician. Blood, stool, and urine were screened for 31 viral, bacterial, fungal, and protozoan agents in addition to biochemical characteristics. The price of advertising, doctor’s visits and diagnostic tests were calculated to determine the cost of finding a donor.ResultsOf the PDs screened, 5 of 46 passed the history, examination, blood, stool, and urine tests. The most common reasons for exclusion included a body mass index >25 or the detection of Blastocystis hominis, Dientamoeba fragilis, or Helicobacter pylori. Four of five eligible donors had subsequent travel or illness that contraindicated donation, so only 1 of 46 PDs was suitable. The total cost for finding a single suitable donor was $15190 US dollars. This screening was performed in Canada, and costs in the United States would be substantially higher.ConclusionsNew potential therapeutic uses for FMT have created a demand for stricter exclusion criteria for donors. This study illustrates that screening many individuals to find a donor and the subsequent associated costs may make central processing and shipment a more reasonable alternative.

The impact of sanity on the fertility of cows submitted to reproductive biotechnics

The productivity in the herds is directly associated with reproduction. Thus, in order to achieve a better efficiency, the most varied reproductive biotechniques have been applied to the plants. Several factors have a direct influence on reproductive performance, including genetics, nutrition, zootechnical management, and sanitation. However, the sanity of the herd through the use of prophylactic measures against infectious agents is often neglected. In this context, particular attention should be paid to health programs, since 37-50% of gestational losses in the herd are consequences of infectious diseases of the reproductive tract caused by viral, bacterial or protozoan agents. Thus, this review will discuss the main advantages obtained with the use of reproductive biotechniques to increase fertility and the epidemiological aspects related to the diseases that cause reproductive failures in cows. Finally, we will also explain the importance of implementing sanitary programs with adequate management and vaccination of animals, to minimize economic losses related to reproductive diseases and, consequently, obtain higher pregnancy rates in the use of reproduction biotechnologies.

Potential of Next-generation POCT in Infectious Disease Rapid Test.

Real-time test results are necessary for early diagnosis and in determining treatment orientation in medical practice. Point of Care Testing (POCT) is a testing system that provides beneficial and helpful information for diagnosis and treatment through real-time testing at the bedside. Therefore, POCT has high utility value in the field of infectious diseases as a rapid test that provides, within the consultation hours, useful information for initial treatment.Infectious disease rapid test kits are commercially available for a wide variety of prophlogistic pathogen targets, including bacterial, viral, fungal, protozoal, and other disease agents. One of these kits is immunochromatography assay (ICA), a measuring method used as POCT that is easy to operate, wherein even physicians and nurses can conduct the test.Serodiagnostic method has been adjunctively used in medical practice in Japan for early clinical diagnosis of deep mycosis as a means to determine treatments. However, this method is complicated and is considered a full-scale clinical examination; therefore, it is not included in the category of POCT. Recently, Loop-Mediated Isothermal Amplification (LAMP) method has been tested as a POCT for diagnosis of fungal infection in the US. Development of a laboratory procedure using simple and highly accurate POCT for early diagnosis of deep mycosis is expected in the near future.

Ixodid ticks in the megapolis of Kyiv, Ukraine

The Ixodidae include the most common tick species encountered in Europe. The ticks transmit a variety of bacterial and protozoan agents of medical and veterinary significance. The aim of the current work was to investigate distribution of Ixodes ricinus and Dermacentor reticulatus ticks in Kyiv, the largest and most densely populated megapolis of Ukraine. Ticks were collected at various recreational areas by flagging during May, the month that showed the highest tick abundance in the past. Sex distribution among I. ricinus ticks was relatively equal, whereas females were collected in higher numbers for D. reticulatus. As opposed to western and central Europe where nymphal ticks had been more abundant, the nymph:adult ratio for I. ricinus was reversed. Also, this report documents detection of Rhipicephalus sanguineus sensu lato (s.l.) in Kyiv region, well outside of its historically documented distribution area. Previously thought to be restricted to the southern Ukraine, a single male specimen of R. sanguineus s.l. was collected just outside the city limits. Data on tick diversity over the past 30 years, however, indicates that this finding may only be incidental.

Pathogenicity and phenotypic sulfadiazine resistance of Toxoplasma gondii isolates obtained from livestock in northeastern Brazil.

Toxoplasma gondii is the causative protozoan agent of toxoplasmosis, which is a common infection that is widely distributed worldwide. Studies revealed stronger clonal strains in North America and Europe and genetic diversity in South American strains. Our study aimed to differentiate the pathogenicity and sulfadiazine resistance of three T. gondiiisolates obtained from livestock intended for human consumption. The cytopathic effects of the T. gondii isolates were evaluated. The pathogenicity was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using a CS3 marker and in a rodent model in vivo. Phenotypic sulfadiazine resistance was measured using a kinetic curve of drug activity in Swiss mice. IgM and IgG were measured by ELISA, and the dihydropteroate synthase (DHPS) gene sequence was analysed. The cytopathic effects and the PCR-RFLP profiles from chickens indicated a different infection source. The Ck3 isolate displayed more cytopathic effects in vitro than the Ck2 and ME49 strains. Additionally, the Ck2 isolate induced a differential humoral immune response compared to ME49. The Ck3 and Pg1 isolates, but not the Ck2 isolate, showed sulfadiazine resistance in the sensitivity assay. We did not find any DHPS gene polymorphisms in the mouse samples. These atypical pathogenicity and sulfadiazine resistance profiles were not previously reported and served as a warning to local health authorities.

Detection of 23 Gastrointestinal Pathogens Among Children Who Present With Diarrhea.

Diarrheal diseases are a major cause of ambulatory care visits and hospitalizations among children. Because of overlapping signs and symptoms and expensive and inefficient testing methods, the etiology of pediatric diarrhea is rarely established. We identified children <18 years of age who were evaluated for diarrhea at Primary Children's Hospital in Salt Lake City, Utah, between October 2010 and September 2012. Stool specimens submitted for testing were evaluated by using the FilmArray gastrointestinal diagnostic system, which is a rapid multiplex polymerase chain reaction platform that can simultaneously detect 23 bacterial, viral, and protozoal agents. A pathogen was detected in 561 (52%) of 1089 diarrheal episodes. The most commonly detected pathogens included toxigenic Clostridium difficile (16%), diarrheagenic Escherichia coli (15%), norovirus GI/GII (11%), and adenovirus F 40/41 (7%). Shiga toxin-producing E coli were detected in 43 (4%) specimens. Multiple pathogens were identified in 160 (15%) specimens. Viral pathogens (norovirus, adenovirus, rotavirus, and sapovirus) were more common among children <5 years old than among those 5 to 17 years old (38% vs 16%, respectively; P < .001). Bacterial pathogens were identified most commonly in children 2 to 4 years of age. Children with 1 or more underlying chronic medical conditions were less likely to have a pathogen identified than those without a chronic medical condition (45% vs 60%, respectively; P < .01). Viral pathogens were detected more commonly in the winter, whereas bacterial pathogens were detected more commonly in the summer. Toxigenic C difficile, diarrheagenic E coli, and norovirus were the leading organisms detected among these children with diarrhea. Viral pathogens are identified frequently among young children with acute gastroenteritis.

Sialic Acid Glycobiology Unveils Trypanosoma cruzi Trypomastigote Membrane Physiology.

Trypanosoma cruzi, the flagellate protozoan agent of Chagas disease or American trypanosomiasis, is unable to synthesize sialic acids de novo. Mucins and trans-sialidase (TS) are substrate and enzyme, respectively, of the glycobiological system that scavenges sialic acid from the host in a crucial interplay for T. cruzi life cycle. The acquisition of the sialyl residue allows the parasite to avoid lysis by serum factors and to interact with the host cell. A major drawback to studying the sialylation kinetics and turnover of the trypomastigote glycoconjugates is the difficulty to identify and follow the recently acquired sialyl residues. To tackle this issue, we followed an unnatural sugar approach as bioorthogonal chemical reporters, where the use of azidosialyl residues allowed identifying the acquired sugar. Advanced microscopy techniques, together with biochemical methods, were used to study the trypomastigote membrane from its glycobiological perspective. Main sialyl acceptors were identified as mucins by biochemical procedures and protein markers. Together with determining their shedding and turnover rates, we also report that several membrane proteins, including TS and its substrates, both glycosylphosphatidylinositol-anchored proteins, are separately distributed on parasite surface and contained in different and highly stable membrane microdomains. Notably, labeling for α(1,3)Galactosyl residues only partially colocalize with sialylated mucins, indicating that two species of glycosylated mucins do exist, which are segregated at the parasite surface. Moreover, sialylated mucins were included in lipid-raft-domains, whereas TS molecules are not. The location of the surface-anchored TS resulted too far off as to be capable to sialylate mucins, a role played by the shed TS instead. Phosphatidylinositol-phospholipase-C activity is actually not present in trypomastigotes. Therefore, shedding of TS occurs via microvesicles instead of as a fully soluble form.

Data on docking and dynamics simulation of Entamoeba histolytica EhADH (an ALIX protein) and lysobisphosphatidic acid.

Entamoeba histolytica is the protozoan agent responsible for human amoebiasis. Trophozoites are highly phagocytic cells and the lysobisphosphatidic acid (LBPA) is involved in endocytosis. LBPA interacts with EhADH protein (an ALIX family member) also participating in phagocytosis, as it is referred in the research article Identification of the phospholipid lysobisphosphatidic acid in the protozoan Entamoeba histolytica: an active molecule in endocytosis (Castellanos-Castro et al., 2016) [1]. To unveil the interaction site between EhADH and LBPA, here we performed molecular modeling, dynamics simulation and docking. Molecular modeling and docking predictions revealed that EhADH interacts with LBPA through the Bro1 domain, located at the N-terminus of the protein and through the adherence domain at the C-terminus. In silico mutation abolished these interactions, supporting the data obtained in molecular dynamic and docking in silico assays.

Case-control study of pathogens involved in piglet diarrhea.

BackgroundDiarrhea in piglets directly affects commercial swine production. The disease results from the interaction of pathogens with the host immune system and is also affected by management procedures. Several pathogenic agents such as Campylobacter spp., Clostridium perfringens, Escherichia coli, Salmonella spp., group A rotavirus (RV-A), coronaviruses (transmissible gastroenteritis virus; porcine epidemic diarrhea virus), as well as nematode and protozoan parasites, can be associated with disease cases.ResultsAll bacterial, viral, protozoan, and parasitic agents here investigated, with the exception of Salmonella spp. as well as both coronaviruses, were detected in varying proportions in piglet fecal samples, and positive animals were equally distributed between case and control groups. A statistically significant difference between case and control groups was found only for Cystoisospora suis (p = 0.034) and Eimeria spp. (p = 0.047). When co-infections were evaluated, a statistically significant difference was found only for C. perfringens β2 and C. suis (p = 0.014).ConclusionsThe presence of pathogens in piglets alone does not determine the occurrence of diarrhea episodes. Thus, the indiscriminate use of antibiotic and anthelminthic medication should be re-evaluated. This study also reinforces the importance of laboratory diagnosis and correct interpretation of results as well as the relevance of control and prophylactic measures.

A survey of tick-borne pathogens in dogs and their ticks in the Pantanal biome, Brazil.

Tick and blood samples collected from domestic dogs in the Brazilian Pantanal were tested by molecular methods for the presence of tick-borne protozoa and bacteria. Among 320 sampled dogs, 3.13% were infected by Babesia vogeli (Piroplasmida: Babesiidae), 8.75% by Hepatozoon canis (Eucoccidiorida: Hepatozoidae), 7.19% by Anaplasma platys (Rickettsiales: Anaplasmataceae), and 0.94% by an unclassified Anaplasma sp. In three tick species collected from dogs, the following tick-borne agents were detected: (a) B. vogeli, An. platys and Ehrlichia canis (Rickettsiales: Anaplasmataceae), infecting Rhipicephalus sanguineus sensu lato (Ixodida: Ixodidae) ticks; (b) H. canis, an unclassified Anaplasma sp. and Rickettsia amblyommii (Rickettsiales: Rickettsiaceae), infecting Amblyomma cajennense sensu lato (Ixodida: Ixodidae) ticks, and (c) Rickettsia sp. strain Atlantic rainforest, an emerging human pathogen, infecting Amblyomma ovale ticks. Molecular analysis, based on a mitochondrial gene, revealed that the Am. cajennense s.l. ticks of the present study corresponded to Amblyomma sculptum, a member of the Am. cajennense species complex, and that Rh. sanguineus s.l. belonged to the tropical lineage. Whereas dogs are exposed to a number of tick-borne bacterial and protozoan agents in the Pantanal biome, humans are potentially exposed to infection by spotted fever group rickettsiae (e.g. R. amblyommii and Rickettsia sp. strain Atlantic rainforest) because both Am. sculptum and Am. ovale are among the most important human-biting ticks in Brazil.