Gene silencing by RNA interference in the ectoparasitic mite, Psoroptes ovis

Abstract The presence of components of the RNA interference (RNAi) pathway in Psoroptes ovis, an ectoparasitic mite responsible for psoroptic mange, was investigated through interrogation of the P. ovis genome. Homologues of transcripts representing critical elements for achieving effective RNAi in the mite, Tetranychus urticae and the model organisms Caenorhabditis elegans and Drosophila melanogaster were identified and, following the development of a non-invasive immersion method of double stranded RNA delivery, gene silencing by RNAi was successfully demonstrated in P. ovis. Significant reductions in transcript levels were achieved for three target genes which encode the Group 2 allergen (Pso o 2), mu-class glutathione S-transferase (PoGST-mu1) and beta-tubulin (Poβtub). This is the first demonstration of RNAi in P. ovis and provides a mechanism for mining transcriptomic and genomic datasets for novel control targets against this economically important ectoparasite

Infestation by Haematopinus quadripertusus on cattle in São Domingos do Capim, state of Pará, Brazil Infestação por Haematopinus quadripertusus em bovinos de São Domingos do Capim, Estado do Pará, Brasil

Severe infestation with lice was observed on crossbred cattle (Bos taurus indicus ×Bos taurus taurus) in the municipality of São Domingos do Capim, state of Pará, Brazil. Sixty-five animals were inspected and the lice were manually collected, preserved in 70% alcohol and taken to the Animal Parasitology Laboratory, School of Veterinary Medicine, Federal University of Pará, Brazil, for identification. The adult lice were identified as Haematopinus quadripertusus, and all the cattle examined were infested by at least one development stage of this ectoparasite. The specimens collected were located only on the tail in 80% (52/65) of the cattle, while they were around the eyes as well as on the ears and tail in 20% (13/65). Nits, nymphs and adults of the parasite were respectively collected from 98.46% (64/65), 38.46% (25/65) and 23.08% (15/65) of the animals examined. This is the first report of bovine pediculosis caused by H. quadripertusus in the state of Pará, Brazil. Further studies should be conducted to determine the occurrence pattern of this species in Brazil and its importance to livestock production.<br>Alta infestação por piolhos foi observada em vacas mestiças Bos taurus indicus e Bos taurus taurus do município de São Domingos do Capim, Estado do Pará, Brasil. Sessenta e cinco animais foram inspecionados e os piolhos foram coletados manualmente, armazenados em álcool 70% e transportados ao Laboratório de Parasitologia Animal da Faculdade de Medicina Veterinária da Universidade Federal do Pará para a identificação. Os exemplares adultos foram identificados como Haematopinus quadripertusus e todos os animais examinados apresentaram pelo menos um estágio de desenvolvimento do ectoparasito. Em 80% (52/65) dos animais, os exemplares coletados localizavam-se somente na cauda e em 20% (13/65) na região periocular, orelha e cauda. Lêndeas, ninfas e adultos foram coletados, respectivamente, em 98,46% (64/65), em 38,46% (25/65) e em 23,08% (15/65) dos animais examinados. Esse é o primeiro relato de pediculose bovina causada por H. quadripertusus no estado do Pará e mais estudos devem ser realizados para determinar a ocorrência dessa espécie no Brasil e a sua importância para a pecuária nacional