Host blood meal analysis of Culicoides oxystoma (Diptera: Ceratopogonidae) in Tunisia

Culicoides are small hematophagous biting midges belonging to the family Ceratopogonidae. The genus is distributed worldwide yet remains poorly studied. This study investigated the vector and host specificity of Culicoides oxystoma, a species of significant relevance to the surveillance of vector-borne diseases in Tunisia and globally. The research was conducted in two Tunisian governments: Tozeur and Kairouan. A total of 24,366 adult midges were collected using two types of suction traps: the Center for Disease Control trap and the Onderstepoort Veterinary Institute trap. Females of Culicoides oxystoma were isolated, carefully dissected, and slide mounted in a phenol alcohol balsam mixture. A portion of the abdomen was excised for total DNA extraction to identify the origin of the blood meal. A total of 108 engorged females were analyzed using polymerase chain reaction (PCR) to amplify specific fragments of the cytochrome b gene, followed by sequencing and sequence analysis. However, DNA sequences were successfully obtained for only 56 individuals. Sequence analysis revealed that the midges fed on a variety of mammalian hosts, including humans, with a prevalence of Mus musculus and Bos taurus. This represents the first study aiming to identify a wide range of hosts in Tunisia and North Africa, providing valuable insights into the hosts utilized by Culicoides oxystoma for blood feeding.