Cryptosporidiosis is an intestinal disease that affects a variety of hosts including animals and humans. Since no vaccines exist against the disease till date, drug treatment is the mainstay of disease control. Nitazoxanide (NTZ) is the only FDA-approved drug for the treatment of human cryptosporidiosis. However, its efficacy in immunocompromised people such as those with AIDS, in malnourished children, or those with concomitant cryptosporidiosis is limited. In the absence of effective drugs against cryptosporidiosis, improving the efficacy of existing drugs may offer an attractive alternative. In the present work, we have assessed the potential of the cell-penetrating peptide (CPP) octaarginine (R8) to increase the uptake of NTZ. Octaarginine (R8) was synthetically attached to NTZ in an enzymatically releasable manner and used to inhibit growth of Cryptosporidium parvum in an in vitro culture system using human ileocecal adenocarcinoma (HCT-8) cell line. We observed a significant concentration-dependent increase in drug efficacy. We conclude that coupling of octaarginine to NTZ is beneficial for drug activity and it represents an attractive strategy to widen the repertoire of anti-cryptosporidial therapeutics. Further investigations such as in vivo studies with the conjugate drug will help to further characterize this strategy for the treatment of cryptosporidiosis.

Ectoparasites not only cause pruritus and dermatitis but also play a crucial role in vector-borne disease in domestic dogs. This study aims to investigate the prevalence of ectoparasite infestation and the molecular characteristics of ticks and fleas. A cross-sectional study was conducted on 720 dogs in two provinces and one city in the Mekong Delta of Vietnam: An Giang, Can Tho, and Kien Giang. The identification of ectoparasites was performed based on parasitological methods, conventional PCR, and sequencing. The findings revealed that domestic dogs were infected ectoparasites with a high infection rate of 57.92% (417/720). Age, lifestyle of dogs, and veterinary management practices of dog owners had a significant influence on the ectoparasite infestation in the surveyed dogs. Six different species of ectoparasites were identified by morphological characteristics, including ticks (Rhipicephalus sanguineus), fleas (Ctenocephalides canis, Ctenocephalides felis felis), demodectic mange (Demodex canis), louse (Trichodectes canis), and mites (Sarcoptes canis). In this study, ticks (R. sanguineus) were the most common ectoparasites in infected dogs (59.95%), followed by fleas (Ctenocephalides spp.) at 34.77%, Trichodectes canis at 6.71%, Demodex canis at 2.63%, and Sarcoptes canis 1.92%. Analyzing the 16S rDNA sequence of R. sanguineus in domestic dogs in the Mekong Delta showed high homologs to the R. sanguineus strains from Brazil and India. Furthermore, the ITS-1 sequence of Ctenocephalides revealed a close relationship to the C. canis isolates in Spain.

Background: Eimeria acervulina is a frequent intestinal pathogen of chickens, causing economic impact on the poultry industry. Cryptosporidium parvum is a neglected parasite in chickens. However, because of its zoonotic potential, poultry cryptosporidiosis may pose a risk to public health. Little is known about the parasite–host interactions during coinfection with both parasites. In this study, we investigated the possible interactions during in vitro coinfection of E. acervulina and C. parvum in a chicken macrophage cell line (HD11). Methods: HD11 cells were inoculated with E. acervulina and C. parvum sporozoites and incubated 2, 6, 12, 24, and 48 h post infection (hpi). Mono-infections for each parasite were also investigated. Real-time PCR was used to quantify parasite replication. Additionally, macrophage mRNA expression levels of IFN-γ, TNF-α, iNOS, and IL-10 were measured. Results: For both parasites, multiplication was, in most groups, lower in the coinfection group (COIG) compared with mono-infections. However, at 6 hpi, the number of C. parvum copies was higher in co-infections. Intracellular replication started to decrease from 12 hpi onward, and it was almost undetectable by 48 hpi in all groups. Infections resulted in low expression of all cytokines, except at 48 hpi. Conclusions: Infection of avian macrophages with both E. acervulina and C. parvum seemed to hinder intracellular replication for both parasites in comparison to mono-infection. A clear reduction in intracellular parasites from 12 hpi onward details the important role potentially played by macrophages in host control of these parasites.

Chicken coccidiosis causes annual losses exceeding GBP 10 billion globally. The most pathogenic species for domestic fowls including Eimeria tenella, E. acervulina, and E. maxima, can lead to gastrointestinal issues ranging from mild to fatal. In this study, stages of E. tenella and freshly isolated chicken heterophils were co-cultured for 180 min. These interactions were analyzed using live 3D holotomographic and confocal microscopy. We observed that E. tenella stages were entrapped by heterophils and heterophil extracellular traps (HETs). Notably, different HET phenotypes, specifically sprHETs and aggHETs, were induced regardless of the stage. Furthermore, the quantification of extracellular DNA release from co-cultures of heterophils and sporozoites (ratio 1:1) for 180 min demonstrated a significantly higher release (p = 0.04) compared to negative controls. In conclusion, research on the chicken innate immune system, particularly fowl-derived HETs, remains limited. More detailed investigations are needed, such as exploring the time-dependent triggering of HETs, to establish a standard incubation time for this pathogen defense mechanism. This will enhance our understanding of its role in parasite survival or death during HET confrontation.

Spirocercosis is caused by Spirocerca spp., which is a chronic disease and might cause life-threatening due to forming cancer in oesophagus in canid carnivores. There are limited studies involving spirocercosis in domestic dogs. Thus, this study aims to investigate the prevalence and analyse risk factors involved in the S. lupi infection in Mekong Delta in Vietnam. In total, 400 fecal samples from domestic dogs were collected from May 2020 to May 2021. The overall prevalence of spirocercosis in domestic dogs in the Mekong Delta was 10.50% by copromicroscope and PCR methods. PCR targeted to the housekeeping gene cytochrome c oxidase I (cox-1) was applied to identify species of Spirocerca spp. and analyse the phylogenetic tree. Outdoor dogs had 5.48 times (CI 95% = 2.45-11.690, p < 0.001) higher risks of S. lupi infection compared to indoor dogs. Besides, seasons and age showed a correlation to the increase the risk of S. lupi infection, while neither dog breeds nor gender influenced the prevalence of this species. The cytochrome c oxidase I (cox-1) gene sequence of S. lupi in the Mekong Delta showed the high homologues to the S. lupi isolates in India, Israel, and the North of Vietnam and belonged to the S. lupi genotype 2.

Caprine coccidiosis is an economic disease in goat husbandry. The study aimed to investigate the prevalence of caprine coccidiosis in the Mekong Delta, Vietnam, and characterization E. arloingi that is one of the most pathogenic and mobile among caprine Eimeria species. Our findings showed that 218 tested samples out of 251 had the presence of Eimeria species, accounting for 86.85 %. The highest infection rate of coccidiosis was recorded in goat kids (< 4-month- old goats) with 96.25%, followed by 88.61% in 4-12 month-old goats and 77.17% in > 12- month-old goats. Four various Eimeria species were morphologically identified, including E. arloingi (43.42%), E. ninakohlyakimovae (39.84%), E. christenseni (33.86%), E. alijevi (12.75%). Molecular characterization of E. arloingi was performed based on two different genes, namely internal transcribed spacer-1 (ITS-1) and 18S rDNA. The phylogenetic trees revealed that E. arloingi had a close relationship to other Eimeria species from goat and sheep. This study confirmed that ITS-1 and 18S rDNA are appropriate genetic markers in the identification and differentiation of Eimeria species in small ruminants.