Dynamically expressed genes provide candidate viability biomarkers in a model coccidian

Eimeria parasites cause enteric disease in livestock and the closely related Cyclosporacayetanensis causes human disease. Oocysts of these coccidian parasites undergo maturation (sporulation) before becoming infectious. Here, we assessed transcription in maturing oocysts of Eimeria acervulina, a widespread chicken parasite, predicted gene functions, and determined which of these genes also occur in C. cayetanensis. RNA-Sequencing yielded ~2 billion paired-end reads, 92% of which mapped to the E. acervulina genome. The ~6,900 annotated genes underwent temporally-coordinated patterns of gene expression. Fifty-three genes each contributed >1,000 transcripts per million (TPM) throughout the study interval, including cation-transporting ATPases, an oocyst wall protein, a palmitoyltransferase, membrane proteins, and hypothetical proteins. These genes were enriched for 285 gene ontology (GO) terms and 13 genes were ascribed to 17 KEGG pathways, defining housekeeping processes and functions important throughout sporulation. Expression differed in mature and immature oocysts for 40% (2,928) of all genes; of these, nearly two-thirds (1,843) increased their expression over time. Eight genes expressed most in immature oocysts, encoding proteins promoting oocyst maturation and development, were assigned to 37 GO terms and 5 KEGG pathways. Fifty-six genes underwent significant upregulation in mature oocysts, each contributing at least 1,000 TPM. Of these, 40 were annotated by 215 GO assignments and 9 were associated with 18 KEGG pathways, encoding products involved in respiration, carbon fixation, energy utilization, invasion, motility, and stress and detoxification responses. Sporulation orchestrates coordinated changes in the expression of many genes, most especially those governing metabolic activity. Establishing the long-term fate of these transcripts in sporulated oocysts and in senescent and deceased oocysts will further elucidate the biology of coccidian development, and may provide tools to assay infectiousness of parasite cohorts. Moreover, because many of these genes have homologues in C. cayetanensis, they may prove useful as biomarkers for risk.

The state of art of neutrophil extracellular traps in protozoan and helminthic infections

Neutrophil extracellular traps (NETs) are DNA fibers associated with histones, enzymes from neutrophil granules and anti-microbial peptides. NETs are released in a process denominated NETosis, which involves sequential steps that culminate with the DNA extrusion. NETosis has been described as a new mechanism of innate immunity related to defense against different pathogens. The initial studies of NETs were carried out with bacteria and fungi, but currently a large variety of microorganisms capable of inducing NETs have been described including protozoan and helminth parasites. Nevertheless, we have little knowledge about how NETosis process is carried out in response to the parasites, and about its implication in the resolution of this kind of disease. In the best case, the NETs entrap and kill parasites in vitro, but in others, immobilize the parasites without affecting their viability. Moreover, insufficient studies on the NETs in animal models of infections that would help to define their role, and the association of NETs with chronic inflammatory pathologies such as those occurring in several parasitic infections have left open the possibility of NETs contributing to pathology instead of protection. In this review, we focus on the reported mechanisms that lead to NET release by protozoan and helminth parasites and the evidence that support the role of NETosis in the resolution or pathogenesis of parasitic diseases.

First detection of tick-borne pathogens of dogs from Malta

The knowledge about the vector-borne infections in domestic dogs has been increasing worldwide. However no studies have been done on hard tick infestation and tick-borne pathogens (TBPs) of dogs present in Malta. Therefore, a total of 99 dogs was selected and inspected between March and July 2013 in 18 urban and 17 rural areas on the islands of Malta and Gozo. All ticks were removed from the dogs and identified. Blood samples were taken and tested for protozoa (Babesia spp. and Hepatozoon spp.) and bacteria (Anaplasma spp., Ehrlichia spp., Rickettsia spp.) by conventional PCR. All of the ticks collected from 34 (34.3%; 95% CI: 26-44) dogs belong to the species Rhipicephalus sanguineus sensu lato. Tick infestation on the farm dogs was significantly higher than that of dogs kept outdoors as pets (OR: 15.19, 95% CI: 2.72-118.92, p<0.001) or in a sanctuary (OR: 35.11, 95% CI: 3.20-1986.67, p<0.001). Altogether 22 animals were infected with one or two TBPs, most of them with Hepatozoon canis (16/22; 72.7%). Anaplasma platys and Babesia vogeli were detected in 5 and 4 dogs, respectively. Three dogs had co-infections caused by H. canis and A. platys. To the best of our knowledge, this is the first report on tick infestation and TBPs of dogs in Malta.

Molecular Characterization of Coccidia Associated with an Epizootic in Green Sea Turtles (Chelonia mydas) in South East Queensland, Australia

In the spring of 2014, mass mortalities among wild green sea turtles occurred off the coast of south-east Queensland, Australia. The suspected causative agent was Caryospora cheloniae, an eimeriid coccidian implicated in previous epizootics. Necropsies were undertaken on a subset of 11 dead turtles, with subsequent histopathology and molecular analyses. All turtles returned positive PCR results for coccidial infection in various tissues; these included the brain, gastrointestinal tract, lung, kidney and thyroid. Granulomatous encephalitis was consistently observed, as well as enteritis and, less frequently, thyroiditis and nephritis. Sequencing and phylogenetic analyses indicated the presence of two distinct coccidian genotypes, presumably separate species—one associated with the brain, gastrointestinal tract and lung, and the second with the thyroid and kidney. Maximum likelihood and Bayesian inference analyses placed the first genotype closest to the lankesterellid genus Schellackia, rather than in the Eimeriidae, while the second was paraphyletic to the eimeriids. Presence of coccidial stages in extra-intestinal tissues of the primary host raises questions about the potential presence of intermediate or paratenic hosts within the life cycles, as well as their current placement relative to the genus Caryospora. This study represents the first genetic characterization of this emerging disease agent in green sea turtles, an endangered species, and has relevance for life-cycle elucidation and future development of diagnostics.

High feather corticosterone indicates better coccidian infection resistance in greenfinches

Differential exposure or sensitivity to stressors can have substantial effects on the variation in immune responsiveness of animals. However, the questions about the causes and consequences of these processes have remained largely unclear, particularly as regards wild animals and their natural pathogens. Here we ask how a potential marker of stress responses, the feather corticosterone (CORT) content, reflects the resistance to an experimental infection with natural coccidian parasites in wild-caught captive greenfinches (Carduelis chloris). CORT content of tail feathers grown in captivity correlated positively with a behavioural measure of captivity-intolerance, i.e., the amount of damage accrued to tail feathers in captivity that results from flapping against cage bars. This finding is consistent with an idea that feather CORT reflects the amount of stress experienced during feather growth. Experimental infection with heterologous coccidian strains increased feather CORT levels. Birds with highest feather CORT levels appeared most resistant to new infection, assessed on the basis of parasite oocyst shedding at the peak phase of infection. Birds with highest feather CORT levels also cleared the infection faster than the birds with lower feather CORT levels. These findings provide the first evidence about positive covariation between feather CORT and resistance to a natural pathogen in a wild bird species. Assuming that feather CORT levels reflect circulating hormone titres, these findings suggest that parasite-mediated selection may contribute to maintenance of phenotypes with high corticosterone responsiveness to stress, despite potential negative behavioural consequences.

Caprine besnoitiosis: an emerging threat and its relationship to some other infections of ungulates by Besnoitia species

Caprine besnoitiosis, caused by the cyst-forming protozoal apicomplexan Besnoitia caprae appears to be endemic in Kenya, Nigeria and Iran, but has yet to be detected in other parts of the world. The infection causes an important parasitic disease of goats in affected developing countries. Bovine besnoitiosis, is a widespread disease of cattle in Africa, Asia (but not Iran) and southern Europe. Recent epidemiological data confirm that the incidence and geographical range of bovine besnoitiosis in Europe is increasing, which is why growing attention has been given to the condition during the past decade. This paper reviews pertinent information on the biology, epidemiology, pathology, clinical signs, diagnosis and control of caprine besnoitiosis, together with its similarities to, and differences from, bovine besnoitiosis. The serious economic consequences of besnoitiosis on goat breeding and local meat and hide industries is also considered.

Differential susceptibility to the Withering Syndrome agent and renal coccidia in juvenile Haliotis rufescens, Haliotis discus hannai and the interspecific hybrid

Withering Syndrome (WS) is a pathogenic chronic disease caused by the intracellular rickettsial-like bacterium "Candidatus Xenohaliotis californiensis" (WS-RLOs), which affects many abalone species. The renal coccidium (Margolisiella haliotis) has often been observed concurrent with WS infection. The red abalone Haliotis rufescens is a very susceptible species to WS and is also infected by the coccidium M. haliotis. In contrast, the Japanese abalone Haliotis discus hannai is not infected by these parasites. Interspecific hybridization is a method for improving important traits in animal husbandry. The objective of this study was to determine susceptibility to WS-RLO and M. haliotis infection in the hybrid generated from a cross between red and Japanese abalones. Juveniles from both species and the interspecific hybrid were challenged by exposure to effluent from red abalone adults infected with both parasites. The animals were analyzed by histology at 130days post-challenge. A 33% prevalence WS-RLOs was observed in the red abalone H. rufescens, whereas a 20% prevalence was observed in the hybrid. Infections were graded on a scale of 0-3. Of these red abalones infected, 53% presented grade 1 infection intensity, 10% had grade 2 infections, and 50% had grade 3 infections. However, the hybrids only presented intensities at the extremes of the scale; of those infected 33% showed grade 1 infections and 66% had grade 3 infections. The coccidium prevalence was 7% in red abalone individuals and 13% in the hybrid abalone. In contrast, the Japanese abalone did not present infections with either parasite. As with the prevalence, the infection intensities for the coccidium were higher in the hybrid abalone; of those infected 25% had grade 2 infections, and 75% had grade 3 infections, but the red abalone presented only grade 2 infection intensities. Therefore, the hybrid did not inherited non-susceptibility or resistance characteristics of the parental H. discus hannai and possessed biological conditions that could foster development of both parasites. Development of a culture based on this hybrid abalone should consider its susceptibility to infection by coccidian, WS-RLOs and the potential for developing the WS disease.

[Dynamics of endoparasite infections in rabbits at different rearing regimes]

This study was intended to evaluate the occurrence and seasonality of infection of coccidian and helminth parasites, in three rabbit warrens differently managed. Mothers stayed with their offspring on deep litter (farm A, 90 dams), in boxes cleaned weekly (farm B, 30 dams) or on slatted floor (farm C, 10 females), whereas all the young after weaning (1 to 5 months of age) were kept in cages with slatted floor. Animals were fed a complete balanced pelleted feed (warrens A and B) or traditional forage (herd C). Antiparasitic treatment involved coccidiostatic drugs. Robenidine (alternately with Lerbec in farm A) was added to food in the first two farms, whilst Sulfatyf mixed with water was given once after weaning in farm C. A total of 203 individual faecal samples from females of breeding stock, and 133 pooled samples from young animals, were collected on an annual cycle during 2007-2008 (February-January), and analyzed according to a modified concentration McMaster method. Coccidians were identified based on sporulated oocysts. A number of coccidian species (Eimeria perforans, E. media, E. magna, E. irresidua, E. exiqua, E. coecicola, and E. piriformis) were observed in all farms. The most pathogenic species--E. intestinalis was found both in farm A and B, whereas E. flavescens and E. stiedae--only in the former. The level of infection was high, especially in young rabbits, with the prevalence of 94.9 to 100% and mean intensity from 11,161 to 28,871 oocysts per 1 g of faeces (OPG) in a particular warren. The highest intensity of infection was observed in May, when the mean output increased to 29,454, 56,952, and 23,815 OPG in warrens A, B, and C, respectively. A nematode, Passalurus ambiguus, was detected in all searched farms, with the prevalence from 14.1% to 27.5%, depending on a farm. The species was more often seen in the first part of year. The other helminths (Trichostrongylus retortaeformis, Graphidium strigosum, and Trichuris leporis) were found only in rabbits of warren C. In this warren, the forage of farm origin was suggested to be prepared in a proper way in order to protect it from nematode transmission. The presence of coccidia and their specific composition has been continuously monitored in all farms, to estimate the efficiency of prophylactic measures undertaken.

Studies on besnoitiosis bennetti in miniature donkeys

Besnoitia tissue cysts associated with the skin lesions recovered from the naturally-infected miniature donkeys (Equus asinus) during clinical examination were studied by the light and electron microscopy, as well as histochemically to elucidate the specific morphologic features of the cyst causing this disease. The cyst was differentiated phenotypically from those of other Besnoitia spp. The interpretation of results showed that morphometric attributes of the tissue cysts and the associated pathological changes in these donkeys were due to B. bennetti infection. The findings were confirmed by the phylogenetic analysis based on DNA sequences of the first internal transcribed spacer of nuclear rDNA. The cluster analysis showed that B. bennetti was distinct from all other Besnoitia spp. and positioned B. bennetti with parasites described from Besnoitia besnoiti of cattle and B. tarandi of reindeer. The genetic attributes complemented the morphological criteria and verified the accurate delimitation of the Besnoitia cysts isolated from these donkeys.

Tissue stages of Hepatozoon canis in naturally infected dogs from Sao Paulo State, Brazil

A total of 222 dogs were examined by blood smear examination and Hepatozoon canis infection was detected in 13 dogs (5.9%). Five H. canis-infected dogs were necropsied to observe tissue stages in the organs. Fragments of spleen, liver, lungs, heart, kidneys, lymph nodes, bone marrow and skeletal muscles were used to made touch-impression smears. No macroscopic lesions were found in the organs. Two dogs had gamonts within polymorphonuclear cells and schizonts in various stages of development within the spleen and the bone marrow. Nevertheless, no mature meronts were found.

Food- and waterborne pathogens: you are (infected by) what you eat!

Coccidia are protozoan parasites responsible for disease worldwide. The orally transmissible stages of coccidia make them food- and waterborne threats. The occurrence of multiple, human-infectious coccidia with diverse life cycles suggests that alterations in host range are a frequent occurrence, and can underlie the rapid emergence of pathogens.

Redescription of Hammondia hammondi and its differentiation from Toxoplasma gondii

Hammondia hammondi is a protozoan parasite that, until 1975, was misidentified as Toxoplasma gondii. Recently, the validity of H. hammondi has been questioned. In this article, the authors redescribe the parasite and its life cycle, provide accession numbers to its specimens deposited in a museum, and distinguish it structurally and biologically from T. gondii. Hammondia hammondi was found to be structurally, biologically, and molecularly different from T. gondii.

Parasitophorous vacuole: morphofunctional diversity in different coccidian genera (a short insight into the problem)

We present a short insight into the problem of parasitophorous vacuole (PV) formation as a most peculiar kind of cell vacuolization occurring in the course of intracellular development of coccidian pathogens of the genera Eimeria, Isospora, Toxoplasma, Sarcocystis, Cryptosporidium, Epieimeria, and Karyolysus. The review focuses on the morpho-functional diversity of PVs in these parasites. By the present time, the PVs containing different parasite genera and species have been examined to different extent. The membrane of the PV (PVM) obviously derives from the host cell plasmalemma. But soon after parasite penetration, the morphofunctional organization and biochemical composition of the PVM drastically changes: its proteins are selectively excluded and those of the parasite are incorporated. As the result, the PV becomes not fusigenic for lysosomes or any other vacuoles or vesicles, because host cell surface markers necessary for membrane fusion are eliminated from the PVM during parasite invasion. The pattern of the PVs is parasite specific and demonstrates a broad diversity within the same genera and species and even at different stages of the endogenous development. The PV is far from being an indifferent membrane vesicle containing the parasite. Instead, it represents a dynamic system that reflects the innermost events of host-parasite relationships, thus promoting the accomplishing of the parasite life cycle, which, in its turn, is a necessary prerequisite of the parasite eventual survival as a species.

Coccidiosis among immuno-competent and -compromised adults

There was significant increase in coccidia positive cases among Hodgkin lymphoma receiving chemotherapy as compared to control group (p < 0.05). The increase was highly significant in the group of acute lymphocytic leukaemia receiving chemotherapy as compared to control group (P < 0.01). The total percent of cases with single type of coccidia were 12.2% compared to multiple coccidial infections (4.3%). The most commonly associated parasite was Cryptosporidium. The total cryptosporidial infections (single and mixed with other coccidia) were 12.1% of the total studied cases. In the immunocompromised the prevalence was 14.3%. In the immunocompetents with diarrhoea, was 8.3% and in control was 5.6%. Microsporidial infections (single and mixed with other coccidia), being the least detected among the four intestinal spores forming coccidia, were 2.4% in the immunocompromised groups. No Microsporidium was detected in the immunocompetent or adult control groups. The total cyclosporal infections (single and mixed with other coccidia) were 6.3% of the total studied cases. In the immunocompromised groups, the prevalence was (8.3%) where in immunocompetent group, was 2.8%. None was detected in the control subjects. Single cyclospora was 3.0% while mixed Cyclospora represented 3.3% of all studied cases. The Isospora infections (single and mixed) were 3.8% of total patients. The prevalence among immunocompromised group was 5.2% and in immunocompetent patients was 2.8%.

Chasing coccidia--new tools enter the race

The 8th International Coccidiosis Conference, held on 9--13 July 2001 in Palm Cove, Australia, was a showcase of the latest studies on widely known coccidia, including Eimeria and Toxoplasma in addition to the emerging or re-emerging parasites such as Neospora, Cryptosporidium and Cyclospora. This meeting was staged in conjunction with the Annual Scientific Meeting of the Australian Society for Parasitology.

An indirect enzyme-linked immunosorbent assay for diagnosis of American canine hepatozoonosis

American canine hepatozoonosis (ACH), caused by Hepatozoon americanum, is an emerging tick-borne disease of dogs. An indirect enzyme-linked immunosorbent assay (ELISA) that should facilitate diagnosis of infection and study of the epidemiology of ACH has been developed using H. americanum sporozoites as antigen. Efficacy of the new test as a diagnostic tool was compared with that of skeletal muscle biopsy, the current gold standard for confirming H. americanum infection. Results show that the test is sensitive (93%) and specific (96%) and that it is as reliable as histopathologic examination of skeletal muscle for detecting infection. The ELISA would be suitable as a routine laboratory test for diagnosis of ACH.

Morphologic and molecular characterization of new Cyclospora species from Ethiopian monkeys: C. cercopitheci sp.n., C. colobi sp.n., and C. papionis sp.n

In recent years, human cyclosporiasis has emerged as an important infection, with large outbreaks in the United States and Canada. Understanding the biology and epidemiology of Cyclospora has been difficult and slow and has been complicated by not knowing the pathogen s origins, animal reservoirs (if any), and relationship to other coccidian parasites. This report provides morphologic and molecular characterization of three parasites isolated from primates and names each isolate: Cyclospora cercopitheci sp.n. for a species recovered from green monkeys, C. colobi sp.n. for a parasite from colobus monkeys, and C. papionis sp.n. for a species infecting baboons. These species, plus C. cayetanensis, which infects humans, increase to four the recognized species of Cyclospora infecting primates. These four species group homogeneously as a single branch intermediate between avian and mammalian Eimeria. Results of our analysis contribute toward clarification of the taxonomic position of Cyclospora and its relationship to other coccidian parasites.

Cyclospora species as a cause of diarrhoea in humans

Within the past 10 years, the coccidian parasite Cyclospora cayetanensis has been clearly recognised as a cause of protracted diarrhoea in humans. Heavy infection results in inflammation and epithelial injury in the duodenum and jejunum. Of the multiple symptoms, diarrhoea may neither be the presenting nor predominant one. Following an incubation period of 12 hours to 11 days, the abrupt onset of watery diarrhoea occurring in a relapsing cyclic pattern is characteristic, lasting from six to eight weeks in immunocompetent patients, but three months in the immunocompromised. Of worldwide distribution, it is endemic in certain regions where it can be associated with rainy seasons. Outbreaks or isolated cases may also occur in developed countries. Contaminated water can transmit the oocysts, and usual control procedures for potable water supplies fail to detect the parasite, which resists chlorination. Diagnosis depends upon laboratory investigations, usually faecal microscopy. For reliable detection of characteristic oocysts in the faeces, special procedures may be necessary. Trimethoprim-sulphamethoxazole is established as the treatment of choice and leads to rapid relief of symptoms, although relapse in immunocompromised patients may require secondary prophylaxis.

Control of coccidiosis: lessons from other sporozoa

Coccidiosis is the most important parasitic infection in poultry worldwide and also causes problems in cattle, sheep and goats. Control is largely limited to good husbandry and prophylactic chemotherapy using a range of drugs against which resistance is rapidly acquired. Attempts at vaccination using conventional vaccines have been disappointing and there is now a need for a new approach. Research into the immunology of coccidiosis has lagged behind that of other sporozoans and there are useful lessons that might be learned from studies on toxoplasmosis, cryptosporidiosis, theileriosis and malaria. In these infections the emphasis has turned to the cytokine network that drives the response towards protection. Central to these studies are the roles of interferon-gamma, interleukin-12 and activated macrophages with the involvement of nitric oxide in parasite killing. Cytotoxic T cells have also increasingly been implicated. Research has shown that different immune responses can be elicited by manipulating the cytokine system and these new concepts can be applied to the design of peptide or recombinant vaccines, and the possibilities of developing such vaccines against coccidiosis will be discussed.

Experimental reproduction of bovine fetal Neospora infection and death with a bovine Neospora isolate

Studies were conducted to determine the pathogenic potential of the recently isolated bovine Neospora protozoa (BPA-1) for the bovine fetus. Cows chosen for study had Neospora titers < 160 using an indirect immunofluorescent antibody (IFA) test. Four experimental groups were studied. In group 1, 2 fetuses were inoculated in utero at 118 days gestation with culture-derived Neospora tachyzoites. A pregnant control cow was housed in the same pen, observed daily and screened serologically for evidence of exposure to Neospora. In group 2, 2 cows were infected with Neospora tachyzoites at 138 or 161 days gestation, and 1 control cow was given uninfected cell culture suspension simultaneously at 154 days gestation. Groups 3 (85 days gestation) and 4 (120 days gestation) each consisted of 2 cows infected with Neospora tachyzoites and 1 control cow given uninfected material at the same stage of gestation. Dead fetuses were surgically removed from the infected cows in group 1 on postinfection day (PID) 17. The histopathology was compatible with protozoal fetal infection, and protozoa were identified by immunohistochemistry. Viable fetuses were removed surgically from cows in group 2 on PID 28-30. The histopathology was compatible with protozoal fetal infection, protozoa were identified by immunoperoxidase techniques, and Neospora tachyzoites were reisolated in vitro from tissues of the 2 infected fetuses. In groups 3 and 4, the control fetus and 1 infected fetus were removed surgically between PID 26 and PID 33. The remaining infected cows were observed until fetal death or abortion occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental infections in domestic ducks with Cryptosporidium baileyi isolated from chickens

Oral inoculation of 13 ducks (Anas platyrhynchos) with 1 x 10(6) Cryptosporidium baileyi oocysts produced patent infections but no clinical signs of disease. Intratracheal inoculation of 13 ducks with 1 x 10(6) C. baileyi oocysts produced only mild clinical signs of respiratory disease, no deaths, and gross lesions of airsacculitis in only three ducks. The distribution of developmental stages of C. baileyi in ducks was similar to that observed in experimentally infected chickens and turkeys. Results of this study indicate that ducks are more resistant to experimentally induced respiratory cryptosporidiosis caused by C. baileyi than are chickens and turkeys.

Infectivity of Cryptosporidium muris (strain RN 66) in various laboratory animals

The infectivity of Cryptosporidium muris (strain RN 66), originally isolated from the house rat (Iseki 1986), to various laboratory animals was studied by transmission experiments. After oral inoculation with 1 x 10(6) oocysts, mice, guinea pigs, rabbits, dogs, and cats all discharged endogenously produced oocysts in their feces. Among these host species, mice and cats were highly susceptible to the parasite. The prepatent period for six 3-week-old specific pathogen-free (SPF) mice was 5 days postinoculation (PI), the patent periods varied between 34 and 75 days for each mouse, and the number of oocysts discharged per individual per day (OPD) was 11-46 x 10(6) at the maximum on days 16-26 PI. The total number of oocysts discharged per mouse during the patent period was estimated to be 170-560 x 10(6). Three inoculated cats (1-2 months old) also discharged a large number of oocysts for a long period. Guinea pigs, rabbits, and dogs showed low susceptibility to this strain; the OPD was extremely small and the patent periods were less than 3 weeks. The entire endogenous development of this parasite occurred in the stomach and not in the small and large intestines of these experimental animals. Because of this lack of host specificity, it is suspected that C. muris could be infective to humans, especially immunocompromised patients such as those with AIDS.

Complete development of Caryospora bigenetica (Apicomplexa: Eimeriidae) in vitro

The development of Caryospora bigenetica in vitro is described by light microscopy. Sporozoites from snake-derived oocysts were purified and inoculated onto cultures of primary testicle cells of the cotton rat, cotton rat kidney cells, and human fetal lung cells. Intracellular sporozoites were observed one and two days postinoculation (DPI). Motile, extracellular first-generation merozoites were present 3 DPI, and second-generation merozoites were present 5 DPI. Mature gamonts were observed 9 DPI and developed into unsporulated oocysts by 10 DPI. Oocystes sporulated in vitro, and excystation was observed. Cells that were penetrated by in vitro-produced sporozoites formed caryocysts by 16 DPI. To test infectivity of in vitro-derived stages, merozoites were removed from cultured cells 5 DPI and inoculated intraperitoneally into a mouse; infection resulted. Sporulated oocysts removed from cell cultures 12 DPI produced facial swelling in an orally inoculated cotton rat.

Hepatozoonosis in foxes from Portugal

Hepatozoon, sp. is described for the first time in foxes (Vulpes vulpes silacea) in Portugal. Of 301 foxes examined, 143 (48%) were infected. The gametocyte was the predominant stage of the life cycle and was found in every organ except the bone marrow, where schizonts were the most abundant stage. The morphological similarity of this parasite's gametocytes to Hepatozoon canis is emphasized.

Experimental Cryptosporidium parvum infections in opossums (Didelphis virginiana)

Five nursing opossums (Didelphis virginiana) were each inoculated with 5 x 10(6) Cryptosporidium parvum oocysts of calf origin. Following inoculation, endogenous stages of C. parvum were observed in the ileum, cecum, and colon of these opossums. Two of three noninoculated pouch mates acquired infections during the study based on examinations of feces and tissue sections of all eight opossums. Mild diarrhea was observed in four of seven opossums harboring C. parvum, although none died as a result of the infection. Under the conditions of this study, C. parvum appeared to be only mildly pathogenic for opossums.

Goats as natural intermediate hosts of Hammondia hammondi

The infectivity of Hammondia hammondi (the G-8 strain) to goats was studied to determine the origin of this strain, because it was originally isolated from feces of a cat fed goat muscles. No clinical signs except fever were observed in kids after oocyst inoculation. When cat fed muscles of these kids, the cats excreted oocysts. The prepatent period was 7 to 9 days and the patent period was 6 to 12 days. From these experiments it became clear that the G-8 strain was infectious to goats. The origin of this strain is very probably the goat, which thus is one of the natural intermediate hosts of H. hammondi.

Effect of drying on the infectivity of cryptosporidia-laden calf feces for 3- to 7-day-old mice

Cryptosporidium-laden calf fecal specimens (n = 13) of various consistencies were infective for infant mice, but infectivity for infant mice ceased after 1 to 4 days of drying.

Experimental intrauterine infection of adult BALB/c mice with Cryptosporidium sp

Inoculation of adult, female BALB/c mice with 2 X 10(5) bleach-treated Cryptosporidium sp. oocysts isolated from calf feces resulted in infection of the uterine mucosa in more than 50% of the animals. Cryptosporidium sp. completed the entire life cycle in the uterus, and infectious oocysts were passed into the vagina. Two methods of application were used to establish intrauterine infection. The inoculum was either injected into the uterus after abdominal surgery or intracervically instilled. Mice were susceptible at all phases of the sexual cycle, but the highest infection rates were obtained during estrus and diestrus. Parasites were demonstrated as early as 5 days postinfection. Phagocytic cells in the uterine lumen and in the vagina contained Cryptosporidium sp. Phagocytosis may be an important immune response and a mechanism of parasitic clearance. These results suggest that Cryptosporidium sp. is a potential pathogen of the reproductive tract.

Host specificity of Cryptosporidium sp. isolated from chickens

The host specificity of Cryptosporidium sp. infecting chickens was evaluated by oral inoculation of oocysts into 6 different species of neonatal rodents, adult nude mice (athymic), neonatal conventional and gnotobiotic pigs, turkeys, muscovy ducks and bobwhite quail. Examinations of tissue sections, ileal mucosal smears, fecal flotations and stained feces failed to reveal any infections in the mammalian species examined. Oocysts were observed in the feces, and developmental stages were observed in tissue sections, of turkeys and muscovy ducks but not bobwhite quail. This study indicates that Cryptosporidium sp. infections in avian species are probably not a zoonotic threat to humans.

Infectivity of Cryptosporidium sp isolated from wild mice for calves and mice

A study was conducted to determine the incidence of cryptosporidiosis in wild mice (Mus musculus) and the infectivity of oocysts from their feces for susceptible calves. The presence of oocysts and the duration of shedding of oocysts in the feces were evaluated in 115 wild mice. Approximately 30% of the mice shed Cryptosporidium sp oocysts, without evidence of clinical infection; recurrence of oocyst shedding was found in about 50% of the mice. Oocysts from the feces of naturally infected mice were infective for calves and mice. Calves began shedding oocysts at 7 days and shed oocysts for about 10 days. Nonfatal, clinical cryptosporidiosis developed in 7 infected calves. The mice began shedding oocysts at 6 days and shed oocysts for 12 days. Fatalities or clinical infection did not develop in 5 infected mice. The results indicated that Cryptosporidium-infected wild mice may be a source of cryptosporidiosis in susceptible calves.

Cryptosporidium species a "new" human pathogen

Publications describing aspects of the coccidian protozoan parasite Cryptosporidium, increased greatly during 1983 and 1984 as a result of not only increasing veterinary interest but also in the role of the parasite in the newly recognised acquired immune deficiency syndrome (AIDS). The reports reflected widespread collaboration, not only between clinicians, microbiologists, and histopathologists, but also between veterinary and human health care workers. Cryptosporidium was first described in mice in 1907 and subsequently in various other species; it was not described in man until 1976. Several likely putative species have been described, but there is probably little host specificity. Experimental and clinical studies have greatly increased the knowledge about the organism's biology. The parasite undergoes its complete life cycle within the intestine, although it may occasionally occur in other sites. The main symptom produced is a non-inflammatory diarrhoea, which, in patients with AIDS and children in Third World countries, may be life threatening: even in immunocompetent subjects this symptom is usually protracted. Attempts to find effective chemotherapeutic agents have been unsuccessful. Epidemiologically the infection was thought to be zoonotic in origin, but there is increasing evidence of person to person transmission. Diagnosis has depended upon histological examination, but simple methods of detection have now been described: more invasive methods need no longer be used. The parasite, which is found more commonly in children, occurs in about 2% of faecal specimens examined and seems to be closely associated with production of symptoms. A serological response has been shown. Much remains to be learned about its epidemiology and pathogenic mechanisms, while the expected increase in incidence of AIDS makes an effective form of treatment essential.

Cryptosporidium spp., a frequent cause of diarrhea in Central Africa

Cryptosporidium oocysts were present in 20 (10.4%) of 193 Rwandese children and in 3 (3.0%) of 100 adults with diarrhea. In four of the children and in one adult, Cryptosporidium was associated with other enteric pathogens. The higher incidence of Cryptosporidium in diarrheic children was statistically significant. The parasite was not found in 94 formed stools submitted for parasitological examination. The mean age of the Cryptosporidium-positive children was 13.3 months. In four children, Cryptosporidium was associated with severe malnutrition. All of those required rehydration, and one child died as a direct consequence of severe diarrhea. The three adult patients showed no recognizable immunodeficiency, and their diarrhea resolved spontaneously. Staining with 1% safranin was not only more simple and rapid but also more sensitive than the modified Ziehl-Neelsen technique.

Experimental cryptosporidiosis in germfree lambs

Contaminating bacteria were removed from an isolate of calf Cryptosporidium by 3 sequential passages of the parasite in gnotobiotic lambs, together with antibiotic treatment of the lambs. This preparation, which contained no detectable bacteria or viruses, was given by mouth to 8 2-day-old gnotobiotic lambs, 3 of which were dosed at the same time with bacterial flora from a healthy calf. Lambs were killed at intervals from 12 to 288 h post-inoculation and the sequential development of the parasite, of enteric lesions, and of clinical illness was observed. Lesions were characterized by severe villus stunting and fusion. Clinically the most consistent sign was anorexia, with some lambs developing also a severe watery diarrhoea. Lesions and clinical signs were similar in lambs with and without intestinal bacteria. This demonstration of the enteropathogenicity of Cryptosporidium in germfree lambs suggests that it is a pathogen of significance.

Experimental cryptosporidiosis in laboratory mice

Eight strains of laboratory mice were susceptible to subclinical infections with Cryptosporidium sp. at 1 to 4 days of age, but only a transient infection could be established at 21 days of age or older. Immunosuppression of 21-day-old mice failed to render them more susceptible to infection. Laboratory storage conditions for Cryptosporidium sp. were investigated by titration in 1- to 4-day-old mice. Storage by freezing with a variety of cryoprotectants was unsuccessful, but storage at 4 degrees C in phosphate-buffered saline or 2.5% potassium dichromate was possible for 4 to 6 months.

Cryptosporidiosis in Idaho lambs: natural and experimental infections

Cryptosporidiosis was diagnosed in lambs of a farm flock and an orphan-lamb rearing operation and in a hospitalized lamb. The clinical course was brief, with mild diarrhea and oocyst shedding during the diarrheic episode. Feces from the hospitalized lamb were used to reproduce the disease. Diarrhea and oocyst shedding occurred in inoculated lambs and their contact twin siblings but not in uninoculated noncontact control lambs or in inoculated ewes.

Experimental infection of piglets with cryptosporidium

Piglets from five litters were doses orally with cryptosporidium originally derived from diarrhoeic calves. The piglets were either nursed by the sow, artificially reared after sucking colostrum, or weaned on to creep feed. Colostrum-fed, artificially reared piglets obtained from two litters and exposed in the first week of life developed clinical signs of inappetence, vomiting and diarrhoea and shed oocysts in the faeces. Histologically the parasite was observed throughout the small and large intestine attached to epithelial cell surfaces and its presence was associated with extensive mucosal damage, particularly in the posterior small intestine, stunting and fusion of villi, immaturity of villous epithelial cells and oedema with increased cellularity of the lamina propria. Piglets from two other litters, both sucking and colostrum-fed artificially reared, exhibited similar but milder clinical signs. Histological lesions were less severe and cryptosporidium infection less extensive. When weaned piglets were exposed they remained clinically healthy although histologically there was evidence of cryptosporidium attachment in the small intestine and minor mucosal damage. There appears to be a good correlation between the extent of intestinal infection, the degree of mucosal damage and the severity of clinical disease induced by cryptosporidium in piglets.

Coccidiosis in Broilers

The Eimeria species in chickens are discussed in a review of the literature. Besides the development of the parasite, attention is paid to the relationship between host and parasite. Recently, immunological features of coccidiosis in broilers are also arousing increasing interest. Not only because of the fact that immunity has been found to play a role in Eimeria infections in broilers despite the use of anticoccidial agents, but also in view of the possibility of vaccination.

[Microsporidiosis and coccidiosis, protozoan diseases of flour beetles (Coleoptera, Tenebrionidae)]

Tribolium destructor and T. confusum diseases caused by the fat body of the parasites Nosema whitei and Adelina tribolii were investigated. Life span and weight dynamics were examined at different temperatures and infection conditions. Infected females of T. confusum lay a less number of eggs. The gas produced by stink glands of T. destructor may inactivate the spores of N. whitei but does not affect those of A. tribolii.