Thelazia lacrymalis in horses from Romania: epidemiology, morphology and phylogenetic analysis

Abstract

Background Equine thelaziosis is a neglected vector-borne parasitic disease in modern veterinary medicine, lacking recent reports. It is transmitted by Musca autumnalis, and potentially other Muscidae species, by ingesting the lachrymal secretions of its equine host. The distribution of both Thelazia lacrymalis and its intermediate hosts remains largely unknown throughout Europe, with most studies dating back 20 years. The aim of this study was to assess the presence, prevalence and distribution of T. lacrymalis in horses from Romania. Methods The eyes of 273 horses, slaughtered at two abattoirs from the Northwestern and Western regions of Romania, were examined for the presence of T. lacrymalis between March and November 2021. Upon detection, the nematodes were collected and morphologically identified using the keys from literature. Following identification, one specimen from each animal was selected for molecular analysis while the rest underwent detailed morphometric measurements. Mapping and distribution, according to ecoregions, was done using the QGis 3.20 software, while sequences obtained were compared to those available in GenBank through BLAST analysis using the MEGA X software. Results Of the 273 animals sampled, 12 (4.39%) were positive for Thelazia spp. infection. Eighty-seven nematodes were recovered, all morphologically identified as T. lacrymalis. The intensity of infestation varied between one and 33 nematodes/animal while five animals presented a bilateral infestation and seven a unilateral one. The highest prevalence was encountered in Pannonian ecoregion (12.12%) while the lowest was in the Alpine ecoregion (0%). Seventy-five intact specimens underwent detailed morphometric analysis, of the 18–20 parameters, resulting in notable differences in striation lengths compared to the data available in other reports. BLAST analysis identified a 96.46–98.60% similarity to the only other COI gene sequence available for T. lacrymalis. Conclusions The current study represents the first report of T. lacrymalis in horses in Romania. The low prevalence rates are probably linked to the wide use of macrocyclic lactones. Graphic Abstract

RNA barcode segments for SARS-CoV-2 identification from HCoVs and SARSr-CoV-2 lineages

“…9 A and B; Supplementary Fig. S3A and B ) ( Cotuțiu et al., 2022 ) and sample sequences sets into the same SD for sequence alignment using offline software such as MEGA. This approach facilitated an intuitional and rapid assessment of the identity and differences of nucleotide sites within one SD ( Cotuțiu et al., 2022 ).…”

The occurrence and molecular identification of Thelazia spp. in European bison (Bison bonasus) in the Bieszczady Mountains

“…It has been proposed that the widespread occurrence of M. domestica and M. autumnalis in the natural and semi-natural environment may result from them being synanthropic fly species connected with livestock husbandry 40 . Although it has been suggested that M. domestica may play a role in Thelazia transmission 8 , M. autumnalis is considered the main vector 43 and might participate in passing the infection between sylvatic and synanthropic ruminant species. As there are no current data of Thelazia occurrence in other wild and domestic ruminants in Poland, it is important to begin regular eyeworm monitoring in areas known to be at risk of thelaziosis in European bison.…”

The Composition of Zoophilic Fly Species in Eastern Ukraine

“…Research on the biodiversity of flies (Diptera) was conducted in different ruminant farming systems in Poland (Nosal et al, 2019). Moreover, studies in farms in Romania have investigated the role of the intermediate host Musca autumnalis (M. autumnalis) in the spread of equine thelasiosis (Cotuțiu et al, 2022).…”