Nasal bot: an emerging parasitic disease in small ruminants in the Brazilian Northeast

Abstract:

From January 2011 to December 2014 were diagnosed 9 outbreaks of Oestrus ovis infection in small ruminants (Outbreaks A-I) in the State of Bahia. The incidence of oestrosis in sheep in outbreak A was 0.5% (1/200), in B 2.2% (2/90), in C 0.8% (1/120), in D 2% (2/100), in E 1% (1/100), in F 3% (1/33), in G 0.6% (1/150), in H 2.5% (5/200), and in I 11.42% (8/70), and 5% (2/40) in goats. Clinical signs associated with parasitism were wheezing, sneezing followed by catarrhal nasal secretion, some restlessness, excessive head movement and walking in circles. The breasts and turbinates were hyperemic, with mucosal edema and presence of O. ovis larvae. All larvae collected from the turbinates ranged from the first to the third stage of development. Some L3 larvae collected at necropsy were incubated and the gray colored Imago with dark abdomen obtained from the pupae measured about 10mm. A descriptive analysis of the climatic conditions was carried out; in the year of investigation the incidence of O. ovis infection has grown (p<0.001), and the lowest mean minimum temperature (p<0.001) caused the development the O. ovis fly, so that there was an introduction of an increased number of these flies into the sheep and goat flocks in state of Bahia with the ideal climatic conditions for their perpetuation.

INDEX TERMS:
Oestrus ovis; oestrosis; nasal cavity; sheep; goats; small ruminants; Bahia