Review of diagnostic procedures and control of some viral diseases causing abortion and infertility in small ruminants in Egypt

Mohamed A Mahmoud,Alaa A Ghazy,Raafat M Shaapan

doi:10.33899/ijvs.2020.127114.1461

Abstract

Sheep and goats represent an essential source of meat, milk and wool production. Infectious viral diseases of small ruminants hinder the expected benefits from these animals. The aim of the present review was to shed light on diagnostic procedures and monitoring of some important infectious viral diseases that affect small ruminants. Border disease (BDV) is caused by Pestiviruses. The affected herds are usually expressed high rates of infertility and production of underweighted-lambs. Affected lambs usually die within days after lambing. A commercial killed whole virus vaccine was produced for BDV. Louping ill (LI) is caused by the Louping ill virus, which is transmitted by Ixods ricinus ticks. The LI virus typically causes fever, anorexia and encephalomyelitis. Death could occur 1-3 days after the beginning of signs. The available Louping ill vaccine is composed of inactivated killed virus. Nairobi sheep disease (NSD) is a tick-born infectious disease caused by Rhipicephalus appendiculatus ticks, characterized clinically by fever, abortion hemorrhagic gastroenteritis and high mortality. Inactivated killed oil adjuvant virus vaccines are available for the control of Nairobi sheep disease. Akabane disease (AKAV) is a Culicoides borne viral disease belongs to orthobunyavirus that has a teratogenic effect on the fetus of cattle and small ruminants. A live attenuated virus vaccine and inactivated virus are commonly used. This review concluded that the modern diagnostic tools are urgently needed not only for diagnosis but also for monitoring viral disease control and control programs.

Highlights

The most common viral infections of sheep and goats in Africa are goats/sheep pox (SGPX), peste des petits ruminants (PPR), contagious ecthyma (CPD or ORF), Rift Valley fever (RVF), bluetongue (BT), Foot and mouth (FMD), Nairobi sheep (NSD) and Border (BD) diseases [1,2]
A live attenuated virus vaccine has been applied in Japan, and inactivated virus vaccine that is appropriate for the emergency vaccination of pregnant animals was used in Australia, Japan and Korea [41]
A live attenuated virus vaccine has been applied in Japan, and inactivated virus vaccines that is appropriate for the emergency vaccination of pregnant animals was used in Australia, Japan and Korea

Summary

Introduction

The most common viral infections of sheep and goats in Africa are goats/sheep pox (SGPX), peste des petits ruminants (PPR), contagious ecthyma (CPD or ORF), Rift Valley fever (RVF), bluetongue (BT), Foot and mouth (FMD), Nairobi sheep (NSD) and Border (BD) diseases [1,2]. Some of sheep and goats viral diseases are transmitted directly from infected animals to the susceptible one (e.g. FMD, PPR, SGPX and CPD), others need an invertebrate host as Culicoides spp. Louping ill virus is a member of the genus Flavivirus (family Flaviviridae) [12] It can affect mainly sheep [13], cattle [14] and red grouse [15], but it affects a wide range animal species including goats [16], pigs [17], dogs [18], horses [19], deer [20,21], alpacas [22] llamas [23] and mountain hares [24]. Nairobi sheep disease can be eliminated by controlling movement, quarantine and euthanasia of infected animals with tick control measures. Due to the differences in antigenicity between BDV and BVDV, analyses needed for the detection of antibodies against BDV by VNT, firstly based on a strain of BDV (Table 1) [43,47]

Method

Conclusion