Genome-wide insights on gastrointestinal nematode resistance in autochthonous Tunisian sheep.

Gastrointestinal nematode (GIN) infections have negative impacts on animal health, welfare and production. Information from molecular studies can highlight the underlying genetic mechanisms that enhance host resistance to GIN. However, such information often lacks for traditionally managed indigenous livestock. Here, we analysed 600 K single nucleotide polymorphism genotypes of GIN infected and non-infected traditionally managed autochthonous Tunisian sheep grazing communal natural pastures. Population structure analysis did not find genetic differentiation that is consistent with infection status. However, by contrasting the infected versus non-infected cohorts using ROH, LR-GWAS, FST and XP-EHH, we identified 35 candidate regions that overlapped between at least two methods. Nineteen regions harboured QTLs for parasite resistance, immune capacity and disease susceptibility and, ten regions harboured QTLs for production (growth) and meat and carcass (fatness and anatomy) traits. The analysis also revealed candidate regions spanning genes enhancing innate immune defence (SLC22A4, SLC22A5, IL-4, IL-13), intestinal wound healing/repair (IL-4, VIL1, CXCR1, CXCR2) and GIN expulsion (IL-4, IL-13). Our results suggest that traditionally managed indigenous sheep have evolved multiple strategies that evoke and enhance GIN resistance and developmental stability. They confirm the importance of obtaining information from indigenous sheep to investigate genomic regions of functional significance in understanding the architecture of GIN resistance.

Dynamics of infestation by Rhinoestrus usbekistanicus in donkeys (Equus asinus) in Tunisia.

Examination of a total of 125 slaughtered donkeys in Tunisian slaughterhouses revealed the presence of 1,508 larvae of Rhinoestrus usbekistanicus in their nasal cavities, with an overall infestation prevalence of 52.8%. The highest overall intensity (number of larvae per infested donkey) and abundance (number of larvae per donkey examined) of infestation were reported in winter (35.6 and 12.1, respectively). Larvae 1 (L1) were the most frequent stage and reached a peak prevalence of 100% during November. The number of larvae 2 (L2) and 3 (L3) was low and the maximum was recorded during March and April. Post-mortem observations showed that infestation intensity increases with age. The ethmoid bone was the most frequently infected portion of the nasal cavity (83.75%). This is the first study on nasal bots in donkeys in Tunisia.

Lors de l'examen des cavités nasales d'un total de 125 ânes abattus dans des abattoirs tunisiens, 1 508 larves de Rhinoestrus usbekistanicus ont été dénombrées, le taux de prévalence de l'infestation s'élevant à 52,8 %. C'est en hiver que l'intensité de l'infestation (nombre de larves par âne infesté) et son abondance (nombre de larves par âne examiné) étaient les plus élevées (elles étaient respectivement de 35,6 et 12,1). Le stade larvaire 1 (L1) était le plus fréquent, avec un pic de prévalence de 100 % en novembre. Le nombre de larves de stade 2 et 3 (L2 et L3) était faible et enregistrait son plus haut niveau aux mois de mars et d'avril. Les observations post-mortem ont montré que l'intensité de l'infestation s'accroît avec l'âge de l'animal. La partie de la cavité nasale le plus souvent infestée était l'os ethmoïde (83,75 % des cas). Il s'agit de la première étude consacrée aux myiases nasales chez l'âne en Tunisie.

Los autores describen un estudio en el cual, tras analizar un total de 125 asnos sacrificados en mataderos tunecinos, se observó en las fosas nasales de parte de ellos la presencia de 1 508 larvas de Rhinoestrus usbekistanicus, con una prevalencia global de infestación del 52,8%. En cuanto a la intensidad (número de larvas por asno infectado) y abundancia (número de larvas por asno analizado) de la infestación, los guarismos globales más elevados se registraron en invierno (35,6 y 12,1 respectivamente). El estadio larvario más frecuente era el primero (L1), cuyo pico de prevalencia, del 100%, se alcanzaba en noviembre. Las larvas de segundo y tercer estadios (L2 y L3) eran poco numerosas, con un máximo registrado en marzo y abril. Las necropsias demostraron que la intensidad de infestación aumenta con la edad. La parte de la fosa nasal infestada con más frecuencia (un 83,75%) era el hueso etmoides. Se trata del primer estudio realizado en Túnez de la presencia de larvas nasales en asnos.

First detection and molecular identification of Sarcocystis spp. in small ruminants in North-West Tunisia.

Sarcocystosis is a parasitic disease caused by varying Sarcocystis species infecting humans and animals. It is commonly found in small ruminants causing pathogenic effects. This contributes to detrimental economic loss for local farmers and the local economy due this disease. Although the distribution of Sarcocystis can be found all over the world, the species infecting small ruminants in Tunisia is still unknown. Through this study, we aim to estimate the molecular prevalence of natural infection with Sarcocystis spp. in sheep and goats using molecular identification. Also, phylogenetic analyses were used to identify the different species of this parasite infecting small ruminants in northern Tunisia for the first time. DNA was extracted from 198 and 121, sheep and goats meat samples, respectively. The molecular prevalence of Sarcocystis spp. in sheep and goats was 58.6% (116/198) and 50.4% (61/121), respectively. Compared to the Noire de Thibar and cross-breeds, the Barbarine sheep had the highest infection prevalence (63.4%) (p = .004). Five of the 116 positive samples were sequenced identifying Sarcocystis tenella from sheep. For goats, the sequencing results showed that five positive PCR products belonged to Sarcocystis capracanis species.

Molecular Study of Dirofilaria immitis and Dirofilaria repens in Dogs from Tunisia.

Dirofilaria immitis and Dirofilaria repens are mosquito-borne nematodes which infect primarily dogs as their main definitive hosts. They cause cardiopulmonary (D. immitis) or cutaneous (D. repens) dirofilariasis in canids and other carnivores and can accidentally be transmitted to humans where they can induce a variety of clinical outcomes depending on organ localization. Dirofilaria spp. infection in dogs was assessed using molecular methods (PCR and sequencing) to identify the different Dirofilaria species occurring in 200 dogs from Northern and Central Tunisia. The overall molecular prevalence of Dirofilaria spp. was 17.5% (35/200). The prevalence of D. immitis (14.5%) was significantly higher than for D. repens (3%). Molecular prevalence of D. immitis was significantly higher in suburban compared to urban and rural regions. There was no difference in molecular prevalence of D. immitis or D. repens according to the dogs' (sex or use). Dirofilaria immitis amplicons (accession numbers KR676386) fall into the same clade with D. immitis from China, India and Taiwan. Comparison of the partial sequences of D. repensITS2 rDNA gene (KR676387) revealed 99.6% similarity with D. repens reported in dogs from USA. It had also 97.6% similarity with D. repens from mosquitoes in Czech Republic. High dog parasite burdens should motivate both medical doctors and veterinarians to consider these frequent infections.

Leishmaniosis (Leishmania infantum infection) in dogs.

The authors present an overview of canine leishmaniosis due to Leishmania infantum. This protozoan is transmitted by sandflies and the disease is frequently characterised by chronic evolution. Cutaneous and visceral clinical signs appear as the infection progresses. Lymph node enlargement, emaciation and skin lesions are the main signs observed in the classical forms of the disease. Control is difficult since infected dogs remain carriers for years and may relapse at any time. The mass screening of infected animals and their treatment or euthanasia represent the best way to reduce the prevalence of this disease in endemic regions. Further research is needed to improve the efficiency of the vaccines available to protect dogs against infection. This disease is zoonotic; in humans, clinical cases are reported mainly in elderly people, the young and those whose immune systems have been compromised.