Emergence of Parafilaria bovicola in Austria.

Alexandra Hund,Hans-Peter Fuehrer,Maria Sophia Unterköfler,Bita Shahi Barogh,Johannes Reithofer,Josef Harl

doi:10.3390/ani11102966

Abstract

Simple SummaryBovine parafilariosis is a disease caused by the helminth Parafilaria bovicola (Filariidae, Nematoda). Flies transmit the parasite, which grows to adulthood in an unknown location in the affected animals. The adult female worms are located in nodules under the skin, which they penetrate and lay their eggs in the fluid leaking from the site. There is virtually no information about Parafilaria bovicola in Austria. In this study, these parasites were documented in the provinces of Lower Austria, Upper Austria, Styria, Salzburg, Carinthia, and Tyrol. With a high number of cases during the 2020 study period, it can be assumed that the number of reports will increase in the near future.Veterinarians reported cases of cutaneous bleeding in cattle in Austria in the spring and summer of 2020. It was our goal to confirm the tentative diagnosis of parafilariosis by identifying Parafilaria bovicola in exudate samples using molecular methods for the first time in Austria. We asked veterinarians in the field to collect exudate from typical lesions on cattle. We performed polymerase chain reactions (PCRs) and sequenced a 674-bp section of the mitochondrial cytochrome oxidase subunit I in all positive samples. Overall, in 57 of 86 samples, P. bovicola was confirmed by PCR in cattle from Lower Austria, Upper Austria, Styria, Salzburg, Carinthia, and Tyrol. Sequencing detected four different haplotypes or genotypes, respectively, indicating multiple routes of introduction. We conclude that parafilariosis has spread in Austria and we expect that the number of reports of clinical signs and losses due to carcass damage will increase in the future.

Highlights

Bovine parafilariosis is a parasitic disease caused by the nematode Parafilaria bovicola that was first described by Tubangui [1] in the Philippines
The L1 larvae are ingested by Musca spp. and develop into infective L3 larvae, which are transmitted to cattle and cause cutaneous bleeding after a long period of prepatency of seven to ten months [3,4]
We conclude that P. bovicola has spread in Austria and is most likely endemic in most parts of the country

Summary

Introduction

Bovine parafilariosis is a parasitic disease caused by the nematode Parafilaria bovicola that was first described by Tubangui [1] in the Philippines. Parafilariosis is characterized by the appearance of raised nodules on the neck and body of cattle, which may bleed profusely [2]. These nodules contain adult ovoviviparous females of P. bovicola, which penetrate the skin and release eggs and microfilariae (L1 larvae) into the serosanguinous fluid leaking from the site. Tubangi had only described two female adult worms morphologically, whereas Daslakow found parafilariosis in 60 of 410 examined cattle. In these, he isolated up to 124 male and female P. bovicola specimens per animal. The author found the parasite in many locations and concluded that it must be widely spread in Romania already [6]

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