Therapeutic Management of Rhinitis and Nasal Myiasis in Sheep.
Six adult sheep were presented with history of sneezing, mucopurulent nasal discharges from last four days. While sneezing, larvae of Oestrus ovis were expelled from the nasal cavity. Oestrus ovis infestation were confirmed by examination of the microscopic structures of 'D' shaped respiratory posterior spiracles. Sheep were treated with Ivermectin, Enrofloxacin and Bromhexine hydrochloride, along with supportive therapy. Improvement in the condition was noticed by the third day of therapy.
Keywords: Ivermectin; myiasis; oestrus ovis; sheep
Oestrus ovis is a cosmopolitan parasite and its larval stages inhabits the nasal passages, sinuses of sheep. Oestrus ovis is well recognized parasite of small ruminants in many parts of the world. The parasite primarily infests sheep but rarely infests goats, camel, deer, reindeer, elk, ibex, dog and man (Hanan, 2013). Infection occurs due to deposition of eggs by adult fly in nostrils of host. Presence of larvae in the nasal cavities and adjoining sinuses of sheep is responsible for reduction in productivity (Papadopoulos et al., 2006). Present communication reports the clinical management of rhinitis due to Oestrus ovis in a sheep flock.
History and Diagnosis
Six adult sheep aged between 3-5 years were presented with history of sneezing, mucopurulent nasal discharges. Out of 31 sheep in flock, 12 sheep showed similar signs. Affected sheep showed clear profuse nasal discharges initially, later turned into mucoid and finally presented mucopurulent with fine streaks of blood. Sneezing, stamping of feet and continues head shaking were observed in effected sheep.
Clinical examination revealed swollen nasal bridge, mucopurulent nasal discharges, head down condition with increased respiration (36/min) (Fig.1).
While forceful sneezing larval stages were expelled from nostrils (Fig. 2). Clinical samples including blood smears, dung samples, nasal discharges were collected for laboratory processing. Blood smears did not reveal any haemoprotozoans. Samples collected from nasal cavities revealed gram positive and gram negative bacterial organisms which were sensitive to Enrofloxacin and Ciprofloxacin.
Expelled larvae from nostrils were collected for their identification. Microscopic examination of larvae revealed transverse bands on dorsal surface of each segment, anterior end was armed with minute paired hooks, posteriorly connected with cephalo--thoraxial skeleton and ventral surface had rows of minute spines. The larvae were confirmed as O. ovis on the basis of 'D' shaped, closed, dark brown coloured, deep stigmal plates with radially arranged respiratory holes (Fig. 3) (Soulsby, 1982).
Treatment and Discussion
Based on history, clinical signs and laboratory findings, present cases were diagnosed as rhinitis due to larvae of Oestrus ovis with apparent secondary infections. Sheep were treated with subcutaneous inj. Ivermectin (Neomec (a)) @ 200 [micro]g/kg b. wt. at weekly twice for four doses, daily oral administration of Enrofloxacin and Bromhexine hydrochloride suspension (Enrotas BH (a)) @ 10 mg/kg b. wt. for five days, intramuscular injections of Chlorpheniramine maleate (Anistamin (a)) @ 5 mg/kg b. wt., Prednisolone (b) @ 5 mg/kg b. wt. for three days.
By the third day of therapy, sheep were comparatively active, partial improvement from sneezing and nasal discharges. By the fifth day of therapy, all the sheep recovered from rhinitis and clear nasal discharges were observed. Every sheep during the treatment period expelled 3-6 larval stages of Oestrus ovis while sneezing. In the present study, nasal discharges were observed due to irritation caused by hooks and spines of larvae in nasal cavity. Larvae present in sinuses are sometimes unable to escape; they die and may gradually become calcified or lead to a septic sinusitis (Radostits et al., 2007). Chronicity of the condition causes reduction in grazing time and loss of body condition. Presence and number of larvae in the sinuses depends on season and activity of individual sheep. In general, 4-15 larvae were found in each sheep but many more may be present (da Silva et al., 2012).
Infestation of O. ovis is usually not life threatening, but occasionally there is bacterial infection that causes encephalitis. Secondary infections often lead to mucopurulent discharge, respiratory distress and sneezing fits in affected animals. Normally O. ovis larvae are confined to nasal cavities and paranasal sinuses of head (Dorchies et al., 2001). In the present study, sheep were treated with Enrofloxacin for management of secondary infections, Bromhexine acts as mucolytic and expectorant which will help to expel the larvae, Prednisolone will help full for management of inflammatory reactions caused by larvae.
Chlorpheniramine maleate reduces sneezing, itching and rhinorrhea. It will act by blocking the effects of histamine, a substance released by cells in body that produce allergy symptoms. Ivermectin is a member of the macrocyclic lactone class of endectocides which have a unique mode of action. Compounds of the class bind selectively and with high affinity to glutamate-gated chloride ion channels which occur in invertebrate nerve and muscle cells. This leads to an increase in the permeability of the cell membrane to chloride ions with hyper polarization of the nerve or muscle cell, resulting in paralysis and death of the parasite.
Authors are thankful to the authorities of the Sri Venkateswara Veterinary University, Tirupati for providing necessary facilities.
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S. Sivajothi (1), B. Sudhakara Reddy (2) and T. Nagendra Reddy (3)
Department of Veterinary Parasitology College of Veterinary Science Sri Venkateswara Veterinary University (SVVU) Proddatur - 516360 (Andhra Pradesh)
(1.) Assistant Professor and Corresponding author. E-mail: email@example.com
(2.) Assistant Professor, Teaching Veterinary Clinical Complex
(3.) Assistant Professor, Department of Veterinary Microbiology.
(a) - Brand of Intas Animal Health, Ahmedabad
(b) - Brand of MSD Animal Health, Pune
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|Title Annotation:||Clinical Article|
|Author:||Sivajothi, S.; Reddy, B. Sudhakara; Reddy, T. Nagendra|
|Date:||Jul 1, 2016|
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