Interactions of Plasmodium juxtanucleare and chicken anaemia virus: establishing a model

Morphological and molecular characteristics of Plasmodium juxtanucleare in layer chicken from three districts of Yogyakarta, Indonesia

Background and Aim

Blood parasite infections in poultry, such as Plasmodium, are a serious threat to the poultry industry due to their potential to cause economic losses. To date, there has been inadequate research on the morphological and molecular detection of the different Plasmodium species that infect poultry in Indonesia. Therefore, this study aimed to analyze the morphological and molecular characteristics of Plasmodium spp. and the several predisposing factors for Plasmodium infection in layer chickens from three districts of Yogyakarta, Indonesia.

Materials and Methods

One hundred and five blood samples from layer chickens were collected from 13 farms located in three districts of Yogyakarta (Sleman, Bantul, and Kulon Progo) between September and November 2022. Blood samples were subjected to microscopic and polymerase chain reaction (PCR) analyses. Sequencing was performed using basic local alignment search tools to identify the nucleotide structure of cytochrome b. Phylogenetic analysis of Plasmodium was performed using the MEGA-X software.

Results

Microscopic examination revealed that 17/105 positives (16.19%) were positive for blood parasite infection. Trophozoites, erythrocytic meronts, and microgametocytes of Plasmodium were found in blood samples. Based on the morphological examination, the species found in the samples was close to Plasmodium juxtanucleare. Polymerase chain reaction examination revealed that 21/60 samples were positive for Plasmodium (35%). The Plasmodium species identified from the sequenced samples were proven to be P. juxtanucleare. The P. juxtanucleare from Thailand was closely related to samples (99.64%-100%) with a genetic distance of 0%-1%. In addition, age, population, and cage type were not significantly associated with Plasmodium infection.

Conclusion

Based on microscopic and PCR examinations, the Plasmodium species found in the three districts of Yogyakarta was P. juxtanucleare. The genetic distance between samples from the three districts of Yogyakarta was closely related (0%-1%) to P. juxtanucleare from Thailand and Japan. There was no correlation between Plasmodium infection and age, cage type, or population.

A new pathogen spillover from domestic to wild animals: Plasmodium juxtanucleare infects free-living passerines in Brazil

Habitat modification may facilitate the emergence of novel pathogens, and the expansion of agricultural frontiers make domestic animals important sources of pathogen spillover to wild animals. We demonstrate for the first time that Plasmodium juxtanucleare, a widespread parasite from domestic chickens, naturally infects free-living passerines. We sampled 68 wild birds within and at the border of conservation units in central Brazil composed by Cerrado, a highly threatened biome. Seven out of 10 passerines captured in the limits of a protected area with a small farm were infected by P. juxtanucleare as was confirmed by sequencing a fragment of the parasite's cytochrome b. Blood smears from these positive passerines presented trophozoites, meronts and gametocytes compatible with P. juxtanucleare, meaning these birds are competent hosts for this parasite. After these intriguing results, we sampled 30 backyard chickens managed at the area where P. juxtanucleare-infected passerines were captured, revealing one chicken infected by the same parasite lineage. We sequenced the almost complete mitochondrial genome from all positive passerines, revealing that Brazilian and Asian parasites are closely related. P. juxtanucleare can be lethal to non-domestic hosts under captive and rehabilitation conditions, suggesting that this novel spillover may pose a real threat to wild birds.

Health and epidemiological approaches of Trypanosoma evansi and equine infectious anemia virus in naturally infected horses at southern Pantanal

Equine infectious anemia virus (EIAV) and Trypanossoma evansi are endemic in Brazilian Pantanal Biome, an important area for livestock production. In this sense, we evaluated the epidemiological single and co-infection effects of T. evansi and EIAV in naturally infected horses in the southern Pantanal wetland by serological tests and hematological assays. Both higher seroprevalence and heath poor condition of the sampled animals were associated with differences in horse management between farms. We found that the negative animals for both infectious agents (NN) represented the major group in F1 (37%), and the smallest group in F2 (19%). Furthermore, we recorded higher EIAV seroprevalence (56%) in F2, compared to F1 (38%). We observed that T. evansi infection was mostly related to young horses, as seen by their higher seroprevalence, ranging from 70.7% in the beginning of the rainy season to 81% in the end of flood period, in comparison with the values of 42% and 68%, respectively, in working animals. on the other hand, working animals showed a higher seroprevalence for EIAV (48%) in both seasons than young horses. We observed that the management of working horses could be a risk factor of EIAV infection. On the other hand, as T. evansi is maintained in the study region by many species of wild mammals, the mechanical transmission through blood-sucking vectors ensures the infection to horses since early. Our results showed that single or co-infection by EIAV and T. evansi caused different degree of anemia in the infected animals. Moreover, the health of horses in Brazilian Pantanal is also influenced by differences in horse management and environmental circumstances.