Studies concerning the development of the myxomatosis monitoring and surveillance program for oryctolagus cuniculus

Abstract

Myxomatosis is one of the most important infectious diseases of rabbits. Large economic losses caused by myxomatosis require the development of effective surveillance and monitoring programs. These programs must have an active and passive surveillance based on the best mix of diagnostic methods. In this paper we propose a combination of passive surveillance of myxomatosis (based on “the definition of the case of myxomatosis”) with active sero-surveillance of myxomatosis (based on ELISA). A count of 1463 rabbits from 120 farms was epidemiologically and clinically evaluated. Out of these, 233 rabbits (15.93%), housed in 22 farms (18.33% of the households under monitoring), with signs of myxomatosis have been recorded. During 2010-2014, competitive ELISA or indirect ELISA assessment of blood serum samples taken from rabbits within the species Oryctolagus cuniculus from the exploitation units in which the passive surveillance was used, generated the following results: positive – 26.99% (105/389), negative – 70.44% (274/389) and inconclusive – 2.57% (10/389). The serum samples taken from rabbits previously vaccinated and tested using ELISA came back with 93.55% (58/62) positive results, 6.45% (4/62) negative ones, and none considered inconclusive. The serum samples taken from unvaccinated rabbits and tested using ELISA came back with 16.48% (45/273) positive results, 80.22% (219/273) negative results and 3.30% (9/273) inconclusive ones. Finally, the serum samples taken from rabbits with unknown history of vaccination and tested using ELISA came back with: 5.56% (3/54) positive results, 92.60% (50/54) negative results, and 1.84% (1/54) inconclusive ones. The passive surveillance of several rabbit breeding units allowed us to highlight the endemic character of myxomatosis in the area, along with an oscillatory character in as much as annual prevalence is concerned, and to pinpoint the value of “the definition of the case of myxomatosis”. Also, the serological surveillance through ELISA techniques (competitive ELISA and indirect ELISA) can constitute an efficient control strategy for myxomatosis, and hence a successful alternative to the classical passive surveillance method, which becomes less efficient in endemic areas.