Seroprevalence, Risk Factors, Detection and Isolation of Peste Des Petits Ruminants Virus from Sheep

Research Article

Austin J Vet Sci & Anim Husb. 2023; 10(4): 1128.

Seroprevalence, Risk Factors, Detection and Isolation of Peste Des Petits Ruminants Virus from Sheep

Milkessa Gelana*

Oromia Agricultural Research Institute, Bako Agricultural Research Center, Animal Health Researcher, Bako, Ethiopia

*Corresponding author: Milkessa Gelana Oromia Agricultural Research Institute, Bako Agricultural Research Center, Animal Health Researcher, Bako, Ethiopia. Tel: +251910189839; +251937750429 Email: mikyabe143@gmail.com

Received: August 23, 2023 Accepted: October 02, 2023 Published: October 09, 2023

Abstract

Cross-sectional study, which combined multistage cluster sampling and simple random sampling, was employed with the objectives of investigating seroprevalence, associated risk factors, molecular detection and isolation of Peste Des Petits Ruminants Virus (PPRV) in sheep from October 2019 to August 2019 in selected districts of Horo Guduru Wollega Zone. A total of 387 serum samples were collected from 58 flocks comprised of 387 sheep population. Competitive Enzyme-Linked Immunosorbent Assay (cELISA) was used to detect the presence of PPRV specific antibodies in the sera of animals. Pearson’s Chi-Square and logistic regression analyses were used to see the association of PPR seroprevalence with potential risk factors. The flock-level overall seroprevalence of PPR was found to be 25.86%. An overall seroprevalence of 6.98% (95% CI: 4.65, 10.00) was recorded in the study areas. The seroprevalence of PPR in sheep was significantly higher in mid-highland than highland and lowland (P=0.029). Though the overall seroprevalence of PPR in this study was low, the seropositivity of sheep was due to natural infection indicating the PPRV infection has been circulating in the study areas. Therefore, regular vaccination should be given for sheep to control and prevent its further distribution and awareness should be created for farmers on identified potential risk factors.

Keywords: c-ELISA; Horo guduru wollega; Isolation; PPRV; PCR; Risk factors; Seroprevalence; Sheep

Introduction

Ethiopia is believed to have the largest livestock population in Africa. According to recent estimates, Ethiopia has 56.71 million cattle, 29.33 million sheep, 29.11 million goats, 1.16 million camels and 56.87 million poultry [1]. The livestock sub-sector accounts for 40% of the agricultural Gross Domestic Product (GDP) and 20% of the total GDP without considering the livestock contribution in terms of traction power, fertilizing and means of transport [2]. Sheep and goats contribute 25% of the meat domestically consumed with a production surplus mainly being exported as live animals. Both species also contribute 50% of the domestic needs in wool, about 40% of skins and 92% of the value of hides and skin exported. The annual production of sheep and goat meat is estimated at 56,560 and 28,650 tons respectively [3]. To fully utilize the untouched livestock potential and address food safety issues, the government has created the Ethiopia Livestock Master Plan (ELMP) in 2015. The animal health part of the plan calls for the establishment of a robust animal health information system; reduced production losses by controlling prioritized diseases; increased export earnings by reinforcing the quarantine, inspection and certification system; decreased impact of zoonotic diseases on public health by controlling them and ensuring safety of animal products, improved infrastructure, and addressing policy issues [4].

On the other hand, studies indicate that the current contributions of the livestock subsector which includes small ruminant production to the national economy to be limited and below the potential [5]. Despite its economic significance, investments in modern animal husbandry are limited, especially in the pastoral areas that are the sources of most animals destined for export markets. Value addition in the livestock sector is limited and exports remain dominated by live animals, thus hampering the sector’s potential to ease high unemployment in rural and urban areas. Inadequate veterinary services, feed shortages, poor infrastructure, insufficient financial services and low levels of technical inputs are well documented in the Ethiopian livestock sector [6]. Infectious diseases are among the major factors which limit the production and productivity of small ruminant resulting in significant negative socio-economic impacts [5]. Regardless of production and disease challenges in Ethiopia; farmers prefer to rear sheep and goats for their low cost of production, prolificacy, their adaptive capacity to the environment through dynamic feeding behavior and fast reproduction cycle and growth rate. The degree to which sheep and goats survive to marketable age is one of the key indicators of the efficiency of their production [7].

Peste des Petits Ruminants (PPR) is an acute, highly contagious, World Organization for Animal Health (WOAH-OIE) notifiable and economically important trans-boundary viral disease of sheep and goats associated with high morbidity and mortality [8]. The PPR virus (PPRV) belongs to the genus Morbillivirus in the family Paramyxoviridae. It is closely related to the rinderpest virus of bovine, distemper virus of dogs and other wild carnivores, human measles virus and Morbilliviruses of marine mammals [9]. Peste des petits ruminants epidemics can cause mortality of 50–80% in unvaccinated sheep and goats populations.

Based on the assumption that goats experience an outbreak every 5 years, estimated an annual sum ranging from 2.47£ per goat at a high loss and 0.36£ per goat at the lowest loss. Peste des petits ruminants is one of the important diseases affecting the productivity of small ruminants [10]. Regardless of declarations by the FAO and OIE of a 2030 target for PPRV eradication, the spread of PPR has been facilitated by inconsistent or very restricted vaccination strategies as well as porous borders of neighboring countries between which there is significant illegal cross border animal trade through long-standing traditional animal trading routes [11].

Peste des petits ruminants became one of the most economically important livestock diseases and currently, it is the global issue causing major economic losses in tropical and sub-tropical countries including Ethiopia. Studies so far conducted provide historical information about the frequency and distribution of PPR in Ethiopia. There was no work done so far concerning PPR antibodies prevalence in the Horo, Jimma Geneti, and Jimma Rare districts of Horo Guduru Wollega Zone.

A baseline survey conducted in 2016 in livestock and fish project sites of Horo Guduru Wollega Zone by Animal Health Research Group of Bako Agricultural Research Center in collaboration with International Livestock Research Institute (ILRI) researchers indicated extensive circulation of PPR virus among sheep and suggested further study needs to be conducted in identified districts of Horo Guduru Wollega Zone. Therefore; the initiation is raised from the economic importance of PPR and information gaps mentioned above-seeking research work in the described place.

Therefore; the objectives of this research work are:

To estimate the seroprevalence of peste des petits ruminants virus infection in sheep in the study areas.

To identify associated risk factors of peste des petits ruminants virus infection in sheep in selected districts of Horo Guduru Wollega Zone.

To detect the genome of the PPRV from specimens collected during the active cases of PPR in sheep in the study areas.

Materials and Methods

Description of the Study Area

The study was conducted in selected districts of Horo Guduru Wollega Zone of Oromia Regional State. Three districts with different agro-ecologies were selected purposively based on their small ruminant population and rearing history (Figure 3). Shambu town which is the seats and capital city of Horo Guduru Wollega Zone administration is located at about 315 km from Addis Ababa (9° 33 10 N latitude and 37° 03 56 E longitude) in the Oromia Regional State, West Ethiopia.

According to the Horo Guduru Wollega Zone Livestock and FISHERY BUREAU (HGWZLFB) report, the livestock population of the Zone is composed of 1,162,212 cattle, 279,487 sheep, 209,768 goats, 135,543 donkeys, 77,349 horses, 14,260 miles and 479,009 poultry [12]. Nearly half of the livestock population of the zone is cattle followed by poultry (Figure 2).