faty
Get Complete Project Material File(s) Now! »
Aetiology
The causal agent of PPR is the peste-des-petits-ruminants virus (PPRV), a virus which was thought to be a rinderpest mutant adapted to grow in sheep and goats due to the similarity in clinical symptoms and from serological analyses and cross-protection experiments (Diallo, 2000). Epidemiological and molecular studies have confirmed the difference between the causal agents of the two diseases. PPRV is classified in the order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Morbillivirus. Other members of the genus Morbillivirus include: rinderpest virus (RPV), the cause of cattle plague; measles virus (MeV), of man and monkey; canine distemper virus (CDV), affecting animals of the family Canidae; feline morbillivirus (FmoPV) of domestic cats; phocine distemper virus (PDV) of seals; and cetacean morbillivirus (CeMV), which affect marine mammals (Gibbs et al., 1979; Barrett et al., 2006; Woo et al., 2012; King et al., 2012).
PPRV is composed of a nucleocapsid surrounded by an envelope. It is a pleomorphic particle with a size varying between 150 and 700 nm, with a mean size of about 500 nm. PPRV is a fragile heat-sensitive virus; it is inactivated by detergents and liquid solvents such as ether and chloroform. It survives for 2.2 min at 56 °C, 3.3 hours at 37 °C, 9.9 days at 4 °C, and 24.2 days at -20 °C. The virus is stable in liquid suspension at pH values ranging from 5.8 to 9.5 (Rossiter, 2004).
Competitive enzyme linked immunosorbent assay (c-ELISA)
A PPRV H-protein-based monoclonal antibody (Mab) competitive enzyme linked immunesorbent assay (c-ELISA) kit (BDSL, UK) was used for the detection of antibodies to PPRV according to the manufacturer’s instruction (Anderson et al., 1991). All serum samples tested in the present study were processed in duplicates and a cut-off value of 50 % was used. The ELISA micro plates were read with an immunoskan reader (Flow laboratories, UK) with an inference filter of 492 nm. The reader was connected to a computer loaded with ELISA data information (EDI) software which was used to automate the reading and calculate the percentage inhibition (PI) values. The OD (optical density) values were converted to percentage inhibition using the following formula: PI = 100 – (OD control or test serum/ OD MAb control) × 100 The samples with PI ≥ 50 % (cut-off) were considered positives for PPRV infection.
1. GENERAL INTRODUCTION AND LITERATURE REVIEW
1.1. GENERAL INTRODUCTION
1.2. HYPOTHESES
1.3. LITERATURE REVIEW
1.4. PURPOSE OF THE PROJECT
1.5. SPECIFIC RESEARCH AIMS
2. MOLECULAR PHYLOGENY OF CURRENT PPRV OUTBREAKS IN NIGERIA
2.1. INTRODUCTION
2.2. MATERIALS AND METHODS
2.3. RESULTS
2.4. DISCUSSION
3. ISOLATION AND FULL GENOME SEQUENCES OF TWO CO-CIRCULATING LINEAGES OF PPRV IN NIGERIA
3.1. INTRODUCTION
3.2. MATERIALS AND METHODS .
3.3. RESULTS
3.4. DISCUSSION
4. DEVELOPMENT OF A LINEAGE-SPECIFIC REAL TIME PCR ASSAY FOR PPRV
4.1. INTRODUCTION
4.2. MATERIALS AND METHODS
4.3. RESULTS
4.4. DISCUSSION
5. SEROPREVALENCE OF PPRV IN NIGERIAN SMALL RUMINANTS
5.1. INTRODUCTION
5.2. MATERIALS AND METHODS
5.3. RESULTS
5.4. DISCUSSION
6. SEROPREVALENCE OF PPRV IN NIGERIAN CAMELS
6.1. INTRODUCTION
6.2. MATERIALS AND METHODS
6.3. RESULTS
6.4. DISCUSSION
7. GENERAL DISCUSSION, CONCLUSION AND RECOMMENDATION
7.1. GENERAL DISCUSSION
7.2. CONCLUSIONS
7.3. LIMITATIONS IN THIS STUDY
7.4. RECOMMENDATIONS
REFERENCES
