Understanding the normal physiology of the body is the key to study the changes that occur due to any infection. It is known that enteric infections play a considerable role in affecting normal body status. Thus, this study was designed for investigating the enteric infections in Arabian camels in Al-Muthanna Province. In this investigation, 588 fecal and blood serum samples (for diarrheic camels only) were collected from the camels in different areas of Al-Muthanna Province, Iraq from both sexes of different ages during the period from October 2020 up to the end of August 2021. The samples were examined using routine microscopic examination techniques, hematological techniques, and ELISA for parasitic and viral identification. Eimeria rajasthani, Isospora orlovi were recorded for the first time in Iraqi camels with clinical signs of diarrhea, dehydration, and emaciation. The study recorded four types of protozoa: Eimeria spp., Isospora, Cryptosporidium and Balantidium coli. The recorded types of Eimeria were E. dromedarii, E. cameli, and E. rajasthani. There was a significant effect of age on infection rates with Eimeria spp. as the highest Eimeria ratio was in ages of less than two years animals. The infection rates were also affected with months which reached the highest ratios of Eimeria in October while the lowest ratio of Eimeria was recorded in July. BVDV infection rate was found in camels that suffered from diarrhea. There is no significant effect of sex on the onset of the viral disease in camels. For hematological parameters, there were significant differences in RBCs, WBCs, Hb, and PCV values in protozoal and BVDV infections. In conclusion, different kinds of protozoal and viral infections were recorded. Some of the recorded infections were associated with acute clinical signs and have zoonotic importance.

Pathogens have traditionally been studied in isolation within host systems; yet in natural settings they frequently coexist. This raises questions about the dynamics of co-infections and how host life-history traits might predict co-infection versus single infection. To address these questions, we investigated the presence of two parasites, a gut parasite (Isospora coccidians) and a blood parasite (Plasmodium spp.), in House Finches (Haemorhous mexicanus), a common passerine bird in North America. We then correlated these parasitic infections with various health and condition metrics, including hematological parameters, plasma carotenoids, lipid-soluble vitamins, blood glucose concentration, body condition, and prior disease history. Our study, based on 48 birds captured in Tempe, Arizona, US, in October 2021, revealed that co-infected birds exhibited elevated circulating lutein levels and a higher heterophil:lymphocyte ratio (H/L ratio) compared to those solely infected with coccidia Isospora spp. This suggests that co-infected birds experience heightened stress and may use lutein to bolster immunity against both pathogens, and that there are potentially toxic effects of lutein in co-infected birds compared to those infected solely with coccidia Isospora sp. Our findings underscore the synergistic impact of coparasitism, emphasizing the need for more co-infection studies to enhance our understanding of disease dynamics in nature, as well as its implications for wildlife health and conservation efforts.

Systemic isosporosis, previously atoxoplasmosis, is a significant cause of mortality in juvenile passerine birds. Recommended treatment regimens are empiric and vary in efficacy. The goal of this study was to determine the pharmacokinetics and pharmacodynamics of ponazuril for treatment of systemic isosporosis. Ponazuril, diluted with water to create an oral suspension (50 mg/ml), was administered (100 mg/kg) to 72 European starlings (Sturnus vulgaris) by a single dose via direct oral gavage (n = 24), a single dose injected into superworm larvae (Zophobas morio; n = 24), or a daily dose mixed with commercial dog food to top-dress feed for 5 d (n = 24). Peak plasma concentrations were 5.84, 2.46, and 9.13 µg/ml for the direct gavage, injected larvae, and top-dressed feed groups, respectively. With repeated dosing, mean plasma concentrations from the top-dressed feed group were maintained between 8.12 to 13.11 µg/ml. Results suggested ponazuril at a dosage of 100 mg/kg administered via direct gavage or top-dressed feed, but not via injected larvae, would exceed the concentrations needed to inhibit merogony of other apicomplexan parasites in cell culture (5 µg/ml). To assess the pharmacodynamics of this dose, seven passerine birds, red-vented bulbuls (Pycnonotus cafer; n = 2), blue-grey tanager (Thraupis episcopus; n = 1), and red-capped cardinals (Paroaria gularis; n = 4), were identified as shedders of systemic Isospora spp. via fecal qPCR. Birds were then treated with ponazuril (100 mg/kg) daily on top-dressed feed for 14 d. Fecal shedding was assessed via qPCR for 6 wk from the initiation of treatment. Treatment was associated with reduction in proportions of fecal shedding during the treatment period and the week following treatment, but shedding resumed in all birds by the end of sampling. Results support that treatment of breeding birds with 100 mg/kg ponazuril could reduce the shedding of active oocysts and decrease risk of clinical infection in susceptible juveniles.

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Twenty-one white-rumped shamas (19 necropsied, 2 biopsied) (Copsychus malabaricus) housed at the San Diego Zoo between 1992 and 2020 were diagnosed with Isospora infection based on evaluation of histologic sections. Review of these cases revealed a consistent histologic lesion characterized by nodular aggregates of atypical epithelioid macrophages containing few intracytoplasmic protozoa, with or without lymphocytic infiltrates. Of the 19 necropsied cases, 16 (84%) had systemic lesions variably affecting the liver, spleen, gastrointestinal tract, lung, pancreas, connective tissues, or bone marrow, while all 21 diagnosed cases had skin involvement. The findings suggest that white-rumped shamas have a unique inflammatory response to isosporosis with a predilection for the skin. Skin may be a diagnostically sensitive sampling site for histologic diagnosis of Isospora in this species.

OBJECTIVE: Members of the genus Isospora commonly infect a wide variety of wild birds. By combining morphometric and genetic data, we are able to differentiate and describe a new apicomplexan parasite, Isospora picoflavae n. sp., from the Northern Yellow-shafted Flicker (Colaptes auratus luteus) in Ontario, Canada.
METHODS: Unsporulated oocysts were observed in intestinal contents obtained during necropsy; these oocysts completed exogenous sporulation within 7 days at room temperature. Complete nuclear 18S rDNA and complete mitochondrial genome sequences were obtained from this previously undescribed Isospora sp. to compare with related coccidia.
RESULTS: Sporulated oocysts were subspherical in shape measuring an average of 22.7 × 21.7 μm (n = 53; mean shape index 1.05) containing a near-spherical polar granule. Sporocysts were ovoidal to ellipsoidal in shape, measuring an average size of 17.0 × 10.5 μm (n = 9; mean shape index 1.62). Sporocyst residuum was concentrated in an irregular, spherical mass in the middle of each sporocyst. The isolated oocysts differed morphologically from other Isospora species reported to infect members of the family Picidae. Based on phylogenetic analyses using either combined nuclear 18S rDNA and mitochondrial cytochrome c oxidase I (COI) sequences or complete mitochondrial genome sequences, this Isospora sp. n. isolated from the Northern Flicker grouped within a clade containing Isospora species described from various passeriform hosts.
CONCLUSIONS: Based on combined morphological and molecular data, the oocysts found in the gastrointestinal contents of Colaptes auratus luteus represent a new species of Isospora named herein as Isospora picoflavae n. sp.

Infection with systemic Isospora species (systemic isosporiasis [SI]) is common in passerine birds and may cause substantial mortality in zoological collections. Ten years of postmortem records of 26 species of captive, nonnative passerine birds maintained at the Zoological Society of London, London Zoo, plus seven free-ranging species found dead within the zoo, were reviewed to assess cause of death and occurrence of SI (presence of merozoites in tissue impression smears and/or polymerase chain reaction [PCR] testing for Isospora DNA). The records of 287 juveniles and adults were reviewed, of which 161 had SI test results. The most common cause of death was physical (trauma, predation, drowning, and hypothermia), diagnosed in 39.0% of cases. Virulent SI was considered the cause of death in only nine individuals from five species (3.1% of all cases, 5.6% of tested birds). However, merozoites were recorded in 36.0% of the 150 individuals examined cytologically (representing 18 of the 33 species), while 45.3% of 53 spleen samples (14 species) were positive for Isospora DNA. Test agreement for the 42 birds tested by both methods was 69.0%. Assuming that the PCR result was correct in these, 37.9% of the 161 birds (21 species) were positive for SI at the time of death. These figures might underestimate prevalence because of poor DNA preservation and low numbers of individuals of some species tested. Eight new 28S rDNA sequences and 12 new internal transcriber spacer 1/2 sequences were amplified. Sequences from individuals of the same host species clustered together, suggesting a single Isospora species, and there was no evidence of overlap among hosts. These results confirm that systemic infection with Isospora species in zoo passerines is generally of low pathogenicity and most likely coevolved with their hosts. Severe disease may occur, however, with overwhelming exposure, secondary to immunosuppression, or following coinfection with another pathogen.

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Cystoisospora belli causes chronic diarrhoea, acalculous cholecystitis, cholangiopathy and disseminated cystoisosporosis in patients with AIDS. Clinical manifestations and histological stages during C. belli infection in a patient with AIDS and liver disease were described. It was possible to identify sporozoite-like structures in the villus epithelium of the duodenum, close to the vascularization that underlies the basal membrane and unizoite tissue cysts near to the vascularization in the lamina propria. Unizoite tissue cysts were found inside of sinusoids in the liver communicating with the central vein and with a bile canaliculus and portal spaces. Based on these findings a hypothesis on C. belli life cycle could consider that the route of migration of unizoite tissue cysts up the liver is via the portal blood. The unizoite tissue cysts located in hepatic portal vein could migrated via sinusoid to central vein and general circulation through the venous system. The unizoite tissue cysts could also return via bile canaliculus to bile duct to portal triad. This hypothesis allows to understand the presence of unizoite stages in blood, the pathway by which the bile ducts become infected and unizoites in the liver being able to behave like hypnozoites that favour relapses and treatment failures.

Diarrhea in an immunocompromised patient has a broad infectious differential. Diagnosis is difficult despite advances in diagnostic modalities. We report a case of a 45-year-old Nigerian woman who immigrated to the United States 2 years ago. She presented to the hospital with gastrointestinal bleeding, newly diagnosed HIV, and disseminated Kaposi sarcoma. During hospitalization, the patient had an onset of watery diarrhea and high eosinophilia. Subsequent stool analysis using multi-parallel real-time quantitative polymerase chain reaction for 13 parasites was positive for Cystoisospora belli. The patient was treated with trimethoprim-sulfamethoxazole, but had relapsed disease when her antibiotics were stopped prematurely. After restarting trimethoprim-sulfamethoxazole, her diarrhea and eosinophilia improved, and she had undetectable Cystoisospora belli DNA on repeat stool quantitative polymerase chain reaction. This case highlights the importance of a thorough workup for diarrhea, including parasites, especially for immunocompromised patients. Antibiotic prophylaxis is recommended in patients with Cystoisospora belli and HIV/AIDS.