Successful experimental infant baboon model for childhood cryptosporidiosis studies.

BACKGROUND: Cryptosporidiosis causes high morbidity and mortality in children under 2 years of age globally. The lack of an appropriate animal model that mimics the pathogenesis of disease in humans has hampered the development and testing of potential therapeutic options. This study aimed to develop and validate an infant baboon infection model of cryptosporidiosis. METHODS: Eighteen immunocompetent weaned infant baboons aged 12 to 16 months were used. The animals were n = 3 controls and three experimental groups of n = 5 animals each inoculated with Cryptosporidium parvum oocysts as follows: group 1: 2 × 104, group 2: 2 × 105, group 3: 2 × 106 followed by daily fecal sampling for oocyst evaluation. Blood sampling for immunological assay was done on the day of infection and weekly thereafter until the end of the experiment, followed by necropsy and histopathology. Statistical analysis was performed using R, SPSS, and GraphPad Prism software. Analysis of variance (ANOVA) and Bonferroni post hoc tests were used for comparison of the means, with p < 0.05 considered as a significant difference. Correlation coefficient and probit analysis were also performed. RESULTS: In all experimental animals but not controls, the onset of oocyst shedding occurred between days 2 and 4, with the highest oocyst shedding occurring between days 6 and 28. Histological analysis revealed parasite establishment only in infected animals. Levels of cytokines (TNF-α, IFN-γ, and IL-10) increased significantly in experimental groups compared to controls. CONCLUSION: For developing a reproducible infant baboon model, 2 × 104 oocysts were an effective minimum quantifiable experimental infection dose.

The effect of Cryptosporidiumparvum, rotavirus, and coronavirus infection on the health and performance of male dairy calves.

The objective of this prospective cohort study was to investigate the effect of bovine coronavirus (BCoV), bovine rotavirus (BRoV), and Cryptosporidiumparvum on dairy calf health and performance and to determine the prevalence of these pathogens. A total of 198 male dairy calves housed at a grain-fed veal facility were examined from June 11, 2018, to October 9, 2018. Calves were fed milk replacer twice daily and housed individually until weaning at 56 d. Once weaned, calves were moved into groups of 5 until they were moved to a finishing facility at 77 d. At the grain-fed veal facility, calves were scored for fecal consistency for the first 28 d and had fecal samples taken on arrival and at 7 and 14 d. Fecal samples were frozen and submitted to a commercial laboratory, where they were tested for BCoV, C.parvum, and 2 groups of BRoV: group A (BRoV A) and group B (BRoV B). Calves were weighed on arrival and at 14, 49, 56, and 77 d using a digital body scale. Treatments for disease and mortalities that occurred over the 77 d were also recorded. Statistical models, including Cox proportional hazards and repeated measures models, were built to determine the effect of infection with 1 of the pathogens. Over the 3 sampling points, 151 (85.8%), 178 (94.2%), 3 (1.5%), and 97 (57.4%) calves tested positive at least once for BCoV, BRoV A, BRoV B, and C.parvum, respectively. The source of the calves and the level of serum total protein measured on arrival were associated with testing positive for a pathogen. Calves that tested positive for C.parvum had an increased proportion of days with diarrhea and severe diarrhea; calves that tested positive for BCoV and BRoV A had an increased proportion of days with severe diarrhea. In addition, calves that tested positive for C.parvum had a higher hazard of being treated for respiratory disease. With respect to body weight, calves that had diarrhea or severe diarrhea had lower body weight at 49, 56, and 77 d. Specifically, calves that had an increased proportion of days with diarrhea showed a reduction in weight gain of up to 15 kg compared to calves without diarrhea. Calves that tested positive for C.parvum had a lower body weight at 49, 56, and 77 d; calves that tested positive for BCoV had a lower body weight at 56 and 77 d. This study demonstrates that the prevalence of BCoV, BRoV A, and C.parvum infection is high in this population of calves and has significant effects on the occurrence of diarrhea and body weight gain. Future studies should evaluate approaches for minimizing the effect of infection with these pathogens to improve the welfare, health, and productivity of dairy calves.

Cryptosporidium: host and parasite transcriptome in infection.

Cryptosporidium is a waterborne gastrointestinal parasite that causes outbreaks of diarrheal disease worldwide. Despite the impact of this parasite on human health there are no effective drugs or vaccines. Transcriptomic data can provide insights into host-parasite interactions that lead to identification of targets for therapeutic interventions. However, for Cryptosporidium, interpreting transcriptomes has been challenging, in part due to the presence of multiple life cycle stages, the lack of appropriate host cells and the inability to culture the parasite through its complete life cycle. The recent improvements in cell culture and the ability to tag and isolate specific life cycle stages will radically improve transcriptomic data and advance our understanding of Cryptosporidium host-parasite interactions.

Comparative evaluation of Cryptosporidium infection in malnourished and well-nourished children: Parasitic infections are affected by the interaction of nutritional status and socio-demographic characteristics.

Cryptosporidium, as a small protozoan parasite, is a leading cause of persistent diarrhea in children in developing countries and has both a short and long-term impact on the growth of children. In the present study, Cryptosporidium infection was compared in malnourished and well-nourished children by modified acid-fast staining, nested-polymerase chain reaction (nested-PCR) and loop-mediated isothermal amplification (LAMP) methods. As a case-control study, Cryptosporidium infection in 94 malnourished children was evaluated and compared with those of 188 age and gender-matched well-nourished children. Oocysts of Cryptosporidium were detected by modified acid-fast staining method. The extracted DNA was amplified by nested-PCR and LAMP techniques. In addition, positive amplicons were directly sequenced for phylogenetic analysis. Cryptosporidium oocysts were found in the stools of two (2.12 %) children who were hospitalized and had diarrhea by nested-PCR while three isolates (3.2 %) were found by LAMP. Cryptosporidium-positive children were more malnourished compared to those who were negative for Cryptosporidium infection but this important finding was not statistically significant. C. parvum was the main species of Cryptosporidium detected in malnourished children in northwest Iran. LAMP can be considered as a sensitive field monitoring assay in patients with low parasite burden. Nutritional status and socio-demographic factors may have interactive effects on the incidence and severity of parasitic diseases.

Prevalence and molecular characterization of Cryptosporidium and Giardia in pre-weaned native calves in the Republic of Korea.

Cryptosporidium spp. and Giardia duodenalis are protozoan parasites that cause diarrhea in humans and animals. Molecular data on Cryptosporidium spp. and G. duodenalis in calves in the Republic of Korea (ROK) is limited; thus, we investigated the prevalence of Cryptosporidium and Giardia in pre-weaned calves, analyzed the association between these parasites and diarrhea, and identified their zoonotic potential for human infection. Fecal samples were collected from 315 pre-weaned calves aged 1-60 days from 10 different regions in the ROK and screened for Cryptosporidium spp. and G. duodenalis using PCR. Overall prevalence of Cryptosporidium spp. and G. duodenalis was 4.4% (n = 14) and 12.7% (n = 40), respectively. Co-infection was not detected. All Cryptosporidium-positive samples were identified as C. parvum after sequence analysis of a small subunit rRNA fragment and further subtyped into zoonotic IIaA15G2R1 (n = 13) and IIaA18G3R1 (n = 1) by DNA sequencing of the 60-kDa glycoprotein gene. To our knowledge, this is the first report of C. parvum IIaA15G2R1 subtype in calves in the ROK. Based on ß-giardin (bg) gene, G. duodenalis-positive samples belonged to assemblages E (n = 36) and A (n = 4), with the latter belonging to subtype A1, the zoonotic genotype. Six subtypes of assemblage E were identified at the bg locus: E1 (n = 6), E2 (n = 3), E3 (n = 13), E5 (n = 1), E8 (n = 1), and E11 (n = 1). The occurrence of C. parvum and G. duodenalis was not associated with diarrhea in pre-weaned Korean native calves. The present results suggest that the prevalence of C. parvum is not related to calf age; in contrast, the prevalence of G. duodenalis was significantly higher in 41-50-day-old calves (odds ratio = 9.90, 95% confidence interval 2.37-41.34; P = 0.001) than in 1-10-day-old calves. Therefore, calves are a potential source of zoonotic transmission, which may have significant public health implications.

Effectiveness of zinc supplementation on diarrhea and average daily gain in pre-weaned dairy calves: A double-blind, block-randomized, placebo-controlled clinical trial.

The objective of this clinical trial was to evaluate the effectiveness of zinc supplementation on diarrhea and average daily weight gain (ADG) in pre-weaned dairy calves. A total of 1,482 healthy Holstein heifer and bull calves from a large California dairy were enrolled at 24 to 48 hours of age until hutch exit at approximately 90 days of age. Calves were block-randomized by time to one of three treatments: 1) placebo, 2) zinc methionine (ZM), or 3) zinc sulfate (ZS) administered in milk once daily for 14 days. Serum total protein at enrollment and body weight at birth, treatment end, and hutch exit were measured. Fecal consistency was assessed daily for 28 days post-enrollment. For a random sample of 127 calves, serum zinc concentrations before and after treatment and a fecal antigen ELISA at diarrhea start and resolution for Escherichia coli K99, rotavirus, coronavirus, and Cryptosporidium parvum were performed. Linear regression showed that ZM-treated bull calves had 22 g increased ADG compared to placebo-treated bulls (P = 0.042). ZM-treated heifers had 9 g decreased ADG compared to placebo-treated heifers (P = 0.037), after adjusting for average birth weight. Sex-stratified models showed that high birth weight heifers treated with ZM gained more than placebo-treated heifers of the same birth weight, which suggests a dose-response effect rather than a true sex-specific effect of ZM on ADG. Cox regression showed that ZM and ZS-treated calves had a 14.7% (P = 0.015) and 13.9% (P = 0.022) reduced hazard of diarrhea, respectively, compared to placebo-treated calves. Calves supplemented for at least the first five days of diarrhea with ZM and ZS had a 21.4% (P = 0.027) and 13.0% (P = 0.040) increased hazard of cure from diarrhea, respectively, compared to placebo-treated calves. Logistic regression showed that the odds of microbiological cure at diarrhea resolution for rotavirus, C. parvum, or any single fecal pathogen was not different between treatment groups. Zinc supplementation delayed diarrhea and expedited diarrhea recovery in pre-weaned calves. Additionally, zinc improved weight gain differentially in bulls compared to heifers, indicating a research need for sex-specific dosing.

[Effect of Cryptosporidium parvum infection on Toll-like receptors of intestinal mucosa in mice].

OBJECTIVE: To investigate the mechanism of Toll-like receptor in intestinal mucosal injury induced by Cryptosporidium parvum infection in mice. METHODS: Totally 30 male BALB/c mice were randomly divided into a normal control group, 1week infection group and 2-week infection group. The mice of the 1-week and 2-week infection groups were sacrificed 7 days and 14 days after the infection respectively, and the mice of the normal control group were sacrificed 14 days after the infection. The model of intestinal infection of C. parvum in mice was built by using the immunosuppressive method and oocyst intragastric administration. The pathological changes of the intestinal mucosa of mice were observed with a light microscope and the villus height, crypt depth and ratio of villus height/crypt depth were measured. The ultrastructure of the intestinal mucosa of mice was observed by a transmission electron microscope (TEM). The expressions of TLR2 and TLR4 in the intestinal mucosa were tested by qPCR and Western blotting. RESULTS: Under the light microscope, the intestinal villi were dropsical, obviously atrophied and shortened, and the submucosal structure was dropsical. The height of chorionic villi and the ratio of villus height to crypt depth in the jejunum of the 1-week and 2-week infection groups were significantly lower than those in the normal control group (all P < 0.05), while the depth of the recess of the former two was significantly increased (all P < 0.05). With the extension of the infection time, the villus height and the ratio of villus height to crypt depth in the jejunum of mice decreased significantly (both P < 0.05), and the crypt depth increased significantly (P < 0.01). The TEM observation showed that the structure of the oocyst of C. parvum in the jejunum of the infected mouse was intact, the villi around the oocyst were abscission seriously, and the oocyst wall was fused with the epithelial cell membrane. The qPCR observation showed that compared with the normal control group, the expressions of TLR2 mRNA and TLR4 mRNA in the intestinal mucosa of the 1-week and 2-week infection groups were significantly higher (all P < 0.05). In addition, the expressions of TLR2 and TLR4 mRNA in the 2-week infection group were significantly higher than those in the 1-week infection group (both P < 0.05). The Western blotting showed that the expressions of TLR2 protein and TLR4 protein in the intestinal mucosa of the 1-week and 2-week infection groups were significantly higher than those of the normal control group (all P < 0.05). Furthermore, the expressions of TLR2 and TLR4 protein in the 2week infection group were significantly higher than those in the 1-week infection group (both P < 0.05). CONCLUSIONS: TLR2 and TLR4 are important receptors for intestinal mucosal recognition of C. parvum. The C. parvum infection may lead to intestinal mucosal damage possibly via the mechanisms associated with the up-regulation of TLR2 and TLR4 expressions.

[The significance of cryptosporidiosis for the health of calves in Switzerland]. / Die Bedeutung der Cryptosporidiose für die Kälbergesundheit in der Schweiz.

INTRODUCTION: Diarrhea in calves is one of the most important cattle diseases in Switzerland. The diagnosis and treatment of calf diarrhea represent a major challenge. Single-celled Cryptosporidium parasites are the most prevalent causative agents of calf diarrhea besides rotavirus in the first weeks of life, and are responsible for about 50% of diarrheal cases. Cryptosporidium parvum has been described as a cause of diarrhea in one to three weeks old calves since the 1970s. Oral ingestion of persistent environmental oocysts results in severe diarrhea lasting four to six days and shedding of large numbers of infectious oocysts. A tiny amount of 10 oocysts is already sufficient to cause disease. Detailed knowledge about the epidemiology and virulence of the different C. parvum strains is still lacking. In addition, current diagnostic tests cannot reliably distinguish between non-pathogenic (e.g. C. bovis) and pathogenic Cryptosporidium species. Until now, no effective therapeutic drug or vaccine against calf cryptosporidiosis has been found. Water-borne epidemics and the zoonotic potential of Cryptosporidium in immunodeficient patients are of great medical importance. The increasing number of cryptosporidiosis cases associated with high infant mortality in less industrialized and impoverished regions (including South-East Asia and sub-Saharan Africa) has intensified the research in recent years. The recent discoveries of new therapeutics against C. parvum may benefit calf medicine in the near future. This review article reports on these new developments, highlights calf cryptosporidiosis in Switzerland and draws attention to a new research project.

INTRODUCTION: La diarrhée chez les veaux est l'une des maladies du bétail les plus courantes en Suisse. Le diagnostic de la cause et le traitement de la diarrhée des veaux représentent un défi majeur. En Suisse, les cryptosporidies sont, avec les rotavirus, l'agent causal le plus fréquent de diarrhée du veau dans les premières semaines et elles sont responsables d'environ 50% des cas. Le parasite unicellulaire Cryptosporidium parvum a été décrit depuis les années 1970 comme un agent de diarrhée chez les veaux d'une à trois semaines. Après ingestion orale d'oocystes persistants dans l'environnement, il se produit après quelques jours une diarrhée sévère de quatre à six jours avec excrétion massive d'oocystes déjà infectieux. Même quelques oocystes persistants dans l'environnement peuvent être pathogènes. Du point de vue épidémiologique, il existe encore de grandes lacunes dans la connaissance de la variabilité suspectée dans la virulence de diverses souches de C. parvum. En outre, des espèces non pathogènes (entre autres Cryptosporidium bovis) peuvent être présentes chez les veaux, qui ne se distinguent pas de C. parvum avec les tests diagnostiques actuels. Jusqu'à présent, aucun médicament efficace sur le plan thérapeutique et aucun vaccin contre la cryptosporidiose du veau n'ont été trouvés. En médecine humaine, les épidémies transmises par l'eau (en particulier aux États-Unis) et l'importance zoonotique des cryptosporidies comme pathogènes opportunistes chez les personnes immunodéficientes jouent un rôle de premier plan. La forte morbidité de la cryptosporidiose associée à une forte mortalité infantile dans les régions les moins industrialisées et les plus pauvres (entre autres en Asie du Sud-Est et en Afrique subsaharienne) ont relancé la recherche sur ces parasites au cours des dernières années. En particulier, la découverte de nouveaux médicaments contre C. parvum est susceptible de bénéficier à la médecine du veau dans un proche avenir. Cet article de synthèse fait le point sur ces nouveaux développements mais surtout sur la cryptosporidiose du veau en Suisse et attire l'attention sur un nouveau projet de recherche.

Bovine cryptosporidiosis: impact, host-parasite interaction and control strategies.

Gastrointestinal disease caused by the apicomplexan parasite Cryptosporidium parvum is one of the most important diseases of young ruminant livestock, particularly neonatal calves. Infected animals may suffer from profuse watery diarrhoea, dehydration and in severe cases death can occur. At present, effective therapeutic and preventative measures are not available and a better understanding of the host-pathogen interactions is required. Cryptosporidium parvum is also an important zoonotic pathogen causing severe disease in people, with young children being particularly vulnerable. Our knowledge of the immune responses induced by Cryptosporidium parasites in clinically relevant hosts is very limited. This review discusses the impact of bovine cryptosporidiosis and describes how a thorough understanding of the host-pathogen interactions may help to identify novel prevention and control strategies.

Pathogenic Mechanisms of Cryptosporidium and Giardia.

Intestinal protozoa are important etiological agents of diarrhea, particularly in children, yet the public health risk they pose is often neglected. Results from the Global Enteric Multicenter Study (GEMS) showed that Cryptosporidium is among the leading causes of moderate to severe diarrhea in children under 2 years. Likewise, Giardia infects approximately 200 million individuals worldwide, and causes acute diarrhea in children under 5 years. Despite this recognized role as pathogens, the question is why and how these parasites cause disease in some individuals but not in others. This review focuses on known pathogenic mechanisms of Cryptosporidium and Giardia, and infection progress towards disease.

Cryptosporidium parvum infection attenuates the ex vivo propagation of murine intestinal enteroids.

Cryptosporidium, a ubiquitous coccidian protozoan parasite that infects the gastrointestinal epithelium and other mucosal surfaces, is an important opportunistic pathogen for immunocompromised individuals and a common cause of diarrhea in young children in the developing countries. One of the pathological hallmarks of intestinal cryptosporidiosis is villous atrophy, which results in a shorter height of intestinal villi. Here, we investigated the effects of Cryptosporidium infection on intestinal epithelial growth, using an ex vivo model of intestinal cryptosporidiosis employing enteroids from mice. We detected infection of enteroids isolated from immunocompetent adult and neonatal mice after ex vivo exposure to Cryptosporidium sporozoites. We observed a significant inhibition of enteroid propagation following infection. Intriguingly, we identified a decreased expression level of intestinal stem cell markers in enteroids following C. parvum infection. We further measured the expression levels of several Wnt antagonists or agonists in infected enteroids, as induction of the Wnt/ß-catenin activation is a key factor for intestinal stem cell function. We detected a markedly increased level of the Dickkopf-related protein 1 and decreased level of the Wnt family member 5a in enteroids after infection. The low density lipoprotein receptor-related protein 5, one of the Wnt co-receptors, is downregulated in the infected enteroids. In addition, increased apoptotic cell death and cell senescence were observed in the infected enteroids. Our results demonstrate a significant inhibitory effect of Cryptosporidium infection on the ex vivo propagation of enteroids from mice, providing additional insights into the impact of Cryptosporidium infection on intestinal epithelial growth.

Life without a Host Cell: What is Cryptosporidium?

Cryptosporidium is a parasite responsible for widespread disease in livestock and humans. Recent phylogenetic reclassification of Cryptosporidium from a coccidian to a gregarine dictates an urgent need to reconsider the biology and behavior of this parasite. Overwhelming data now confirm that, like its close relatives, Cryptosporidium is a facultatively epicellular apicomplexan that is able to multiply in a host cell-free environment. We complement the latest phylogenetic and taxonomic proposals with advances in our understanding of Cryptosporidium's biology, with particular focus on in vitro studies that have characterized the development of Cryptosporidium stages in the absence of host cells. Opportunities to revisit in vivo infections are discussed and questions about the Cryptosporidium host cell-free life cycle that remain unanswered highlighted.

Early Life Antibiotic Exposure Is Not Associated with Growth in Young Children of Vellore, India.

OBJECTIVES: To estimate the effects of antibiotic exposures in the first 6 months of life on short- and long-term growth. STUDY DESIGN: In a prospective observational cohort study of 497 children from Vellore, India, we estimated short-term effects of antibiotics during the first 6 months using longitudinal general linear regression to model weight-for-age, height-for-age, and weight-for-height z-scores in monthly intervals. To estimate long-term effects, we modeled growth from 6 months to 3 years as a function of antibiotic use in the first 6 months. We also estimated the effects of antibiotics on the monthly relative risks of underweight, stunting, and wasting in the first 6 months and to 3 years. RESULTS: Underweight, stunting, and wasting were common in this population: 31%, 32%, and 15% on average after 6 months of age, respectively. There was no association between antibiotic exposures before 6 months and growth during that period. From 6 months to 3 years, adjusted absolute differences in weight and height were small (approximately -100 g and no more than -2 mm overall, respectively) and not statistically significant. CONCLUSIONS: Antibiotic exposures early in life were not associated with increased or decreased growth. The combination of malnutrition and recurrent illness likely complicate the relationship between antibiotic exposures and growth among children in low and middle-income countries.

Electrical impedance sensor for quantitative monitoring of infection processes on HCT-8 cells by the waterborne parasite Cryptosporidium.

Cryptosporidium is the main origin of worldwide waterborne epidemic outbreaks caused by protozoan parasites. Its resilience to water chemical treatments and the absence of therapy led to consider it as a reference pathogen to assess water quality and as a possible bioterrorism agent. We here show that an electrical impedance-based device is able to get insights on Cryptosporidium development on a cell culture and to quantify sample infectivity. HCT-8 cells were grown to confluency on Interdigitated Microelectrode Arrays (IMA's) during 76h and then infected by Cryptosporidium parvum during 60h. The impedimetric response was measured at frequencies ranging from 100Hz to 1MHz and a 7min sampling period. As the infection progresses the impedance signal shows a reproducible distinct succession of peaks at 12h post infection (PI), 23h PI and 31h PI and local minima at 9h PI, 19h PI and 28h PI. An equivalent circuit modeling-based approach indicates that these features are mostly originated from paracellular pathway modifications due to host-parasite interactions. Furthermore, our data present for the first time a real-time monitoring of early parasitic stage development with alternating zoite and meront predominances, observed respectively at peaks and local minima in the impedimetric signal. Finally, by quantifying the magnitude of the impedimetric response, we demonstrate this device can also be used as an infectivity sensor as early as 12h PI thus being at least 6 times faster than other state of the art techniques.

Correlation between diarrhea severity and oocyst count via quantitative PCR or fluorescence microscopy in experimental cryptosporidiosis in calves.

Cryptosporidium is an important diarrhea-associated pathogen, however the correlation between parasite burden and diarrhea severity remains unclear. We studied this relationship in 10 experimentally infected calves using immunofluorescence microscopy and real-time polymerase chain reaction (qPCR) (N = 124 fecal samples). The qPCR data were corrected for extraction/amplification efficiency and gene copy number to generate parasite counts. The qPCR and microscopic oocyst quantities exhibited significant correlation (R(2) = 0.33, P < 0.05), however qPCR had increased sensitivity. Upon comparison with diarrhea severity scores (from 0 to 3), a PCR-based count of ≥ 2.6 × 10(5) parasites or an immunofluorescence microscopy count of ≥ 4.5 × 10(4) oocysts were discriminatory predictors of moderate-to-severe diarrhea (versus no-to-mild diarrhea), with accuracies and predictive values of 72-82%. In summary, a quantitative approach for Cryptosporidium can refine predictive power for diarrhea and appears useful for distinguishing clinical cryptosporidiosis versus subclinical infection.

Surto de criptosporidiose em bezerros no Sul do Rio Grande do Sul / Outbreak of cryptosporidiosis in calves in Southern Brazil

Descrevem-se os aspectos epidemiológicos, sinais clínicos e a patologia de um surto de criptosporidiose em bezerros na região Sul do Rio Grande do Sul. De um lote de 400 bezerros de 30-45 dias de idade, 35 adoeceram e 16 morreram. Os bezerros nasciam fracos e logo após o nascimento apresentavam diarreia amarela, emagrecimento progressivo, desidratação, depressão e morte entre 10 e 15 dias após o início dos sinais clínicos. Na necropsia havia congestão dos vasos sanguíneos intestinais e mesentéricos. Havia distensão intestinal por gás e dilatação de vasos linfáticos. Microscopicamente havia achatamento das vilosidades intestinais, com necrose e atrofia. Aderidas à superfície das células epiteliais das vilosidades, havia estruturas puntiformes basofílicas de 2-5µm de diâmetro compatíveis com Cryptosporidium spp. A microscopia eletrônica revelou a presença de diferentes estágios do agente aderidos às microvilosidades de enterócitos. Alerta-se para a importância da criptosporidiose como agente primário de diarreia em bezerros. São necessárias medidas preventivas no que se refere ao manejo para diminuir as perdas econômicas e a contaminação ambiental, e, ainda, diminuir o risco para a saúde pública...

This paper describes the epidemiology, clinical signs and pathology of an outbreak of cryptosporidiosis in calves in Southern Brazil. Thirty-five out of 400 calves with 30-45 days of age were affected and 16 died. The calves were born weak and just after birth they had yellow diarrhea, weight loss, dehydration, depression, and death between 10 and 15 days after onset of clinical signs. Congestion of the bowel and mesenteric blood vessels were observed at necropsy. Intestinal distension by gas and dilation of lymphatic vessels were also observed. Microscopically, the intestine showed flattening of the villi with necrosis and atrophy. Adhered to the surface of the villus epithelial cells there were round basophilic structures of 2- to 5-μm-diameter compatible with Cryptosporidium spp. Electron microscopy revealed the presence of different stages of the agent adhered to the microvilli of enterocytes. We alert the importance of cryptosporidiosis as a primary agent of diarrhea in calves. Preventive measures to reduce economic losses, environmental contamination, and also decrease of risk for public health are necessary...

Infectivity of Cryptosporidium andersoni and Cryptosporidium muris to normal and immunosuppressive cynomolgus monkeys.

Cryptosporidium andersoni and Cryptosporidium muris infections have been found in the mice and/or cattle. The oocysts of C. andersoni and C. muris have been sporadically detected in human feces, but the infectious capacity and features have been unknown, because of the scarcity of reports involving human infections. To assess the infectivity and the clinical and pathological features of C. andersoni and C. muris in primates, an experimental infectious study was conducted using cynomolgus monkeys. The monkeys were orally inoculated with oocysts of two different C. andersoni Kawatabi types and C. muris RN-66 under normal and immunosuppressive conditions. The feces of the monkeys were monitored for about 40 days after the administration of oocysts using the flotation method, but no shedding oocysts were observed under either both normal or immunosuppressive conditions. Gross and histopathological examinations were performed on the immunosuppressive monkeys, but these revealed no evidence of Cryptosporidium infections, even though the monkeys were subjected to immunosuppressive conditions. It is hypothesized that C. andersoni and C. muris pose little danger of infection in primates even under immunosuppressive conditions.

[Changes in the heart of neonatal rats after cryptosporidial gastroenteritis of different degrees of severity].

Disturbances at the childhood age increase risk of the appearance of cardiovascular diseases decades later. The nature of this interconnection called ontogenetic programming is not completely understood. Valuable sources of knowledge about mechanisms of ontogenetic programming are data of interspecies study of biology of the body life cycles and of heart physiological capabilities. Taken into account the interspecies differences, these data allow finding the correct direction of experimental investigations. Results of studies of almost 100 homoiothermal species have shown the slow growth and a high loading on the heart at postnatal development to decrease its aerobic capability in adults. Basing on these data, we suggested that the neonatal gastroenteritis causing tachyarrhythmia, malabsorption, and the growth deceleration might lead to pathological changes in the heart. Our task was to evaluate the effect of cryptosporidial gastroenteritis of different degrees of severity on heart of the neonatal rats. By using methods of Real-Time PCR, immunocytochemistry, image analysis, and study of interatrial septum, we have established that a gradual increase of intensity of infestation with Cryptosporidium parvum oocytes causes sharp changes corresponding to the "all or nothing" response. At a weak infestation the interatrial septum was close (like in control), while significant changes in expression of isoforms of heavy chains of alpha- and beta-myosin were absent. At the intermediate and severe infestation, in the interatrial septum the foramen ovale was visualized and there were observed cardiac atrophy and a strong shift of ration of expression of myosin heavy chains toward the low-velocity beta chain. Thus, by disturbing the frequency-strength ratios and causing outflow of resources from the formed heart, the neonatal gastroenteritis produces pathological changes of the organ molecular and anatomical structures. Our results can be interest to evolutionary biologists and physicians, as they show importance of knowledge of evolutionary-comparative investigations for the search for novel risk factors of heart diseases and demonstrate interconnection between gastroenteritis, pathology of interatrial septum, and a change of composition of the main contractile proteins in cardiomyocytes.