Characteristic and non-characteristic pathological findings in peste des petits ruminants (PPR) of sheep in the Ege district of Turkey

Clinical Manifestation and Phylogenetic Analysis of Peste des Petits Ruminants in Local Iraqi Breed Sheep in Al-Diwaniyah Province

Peste des petits ruminants (PPR), a contagious virus that infects sheep and goats, damages livestock globally. This study examined the clinical features and phylogenetic analysis of the PPR virus in Iraqi breed sheep from Al-Diwaniyah province. A clinical trial of 610 sheep from different flocks found 150 oral lesions. Special primers for RT-PCR and Mega11 for phylogenetic analysis were used to study the PPR virus nucleoprotein (N) gene. The PPR infection rate was 44.6% in 4-12 month olds (n = 33/131) and 4.8% in 36-48 month olds (n = 3/75). A 608-bp PPR virus partial N gene sequence was found in 49.3% of samples by RT-PCR. In leucine, isoleucine, proline, glycine, alanine, glutamine, asparagine, threonine, serine, arginine, and lysine codons, 25 amino acid alterations were found. The protein codon 56 alanine-valine alteration was most significant. Moving from a smaller hydrophobic amino acid to one with a bigger side chain may reduce protein stability. Steric hindrance or protein shape change from Valine's extended side chain may impact folding, stability, functionality, and interactions with other molecules. Furthermore, phylogenetic analysis showed that the Nigerian strain (MN271586) was most similar to our Iraqi strain, with 100% identity and coverage. This study found the Peste des Petits Ruminants (PPR) virus in sheep flocks in Al-Diwaniyah Governorate, Iraq, which is genetically similar to neighboring countries. PPR virus strains must be monitored and genetically characterized since N gene alterations can affect infection and propagation.

Determination of Intestinal Viral Loads and Distribution of Bovine Viral Diarrhea Virus, Classical Swine Fever Virus, and Peste Des Petits Ruminants Virus: A Pilot Study

The aim of this pilot study was to determine viral loads and distribution over the total length, at short distances, and in the separate layers of the intestine of virus-infected animals for future inactivation studies. Two calves, two pigs, and two goats were infected with bovine viral diarrhoea virus (BVDV), classical swine fever virus (CSFV), and peste des petits ruminants virus (PPRV), respectively. Homogenously distributed maximum BVDV viral loads were detected in the ileum of both calves, with a mean titer of 6.0 log10 TCID50-eq/g. The viral loads in colon and caecum were not distributed homogenously. In one pig, evenly distributed CSFV mean viral loads of 4.5 and 4.2 log10 TCID50-eq/g were found in the small and large intestines, respectively. Mucosa, submucosa, and muscular layer/serosa showed mean viral loads of 5.3, 3.4, and 4.0 log10 TCID50-eq/g, respectively. Homogenous distribution of PPRV was shown in the ileum of both goats, with a mean viral load of 4.6 log10 TCID50-eq/g. Mean mucosa, submucosa, and muscular layer/serosa viral loads were 3.5, 2.8, and 1.7 log10 TCID50-eq/g, respectively. This pilot study provides essential data for setting up inactivation experiments with intestines derived from experimentally infected animals, in which the level and the homogeneous distribution of intestinal viral loads are required.

Peste des petits ruminants in Africa: Meta-analysis of the virus isolation in molecular epidemiology studies

Peste des petits ruminant (PPR) is a highly contagious, infectious viral disease of small ruminant species which is caused by the peste des petits ruminants virus (PPRV), the prototype member of the Morbillivirus genus in the Paramyxoviridae family. Peste des petits ruminant was first described in West Africa, where it has probably been endemic in sheep and goats since the emergence of the rinderpest pandemic and was always misdiagnosed with rinderpest in sheep and goats. Since its discovery PPR has had a major impact on sheep and goat breeders in Africa and has therefore been a key focus of research at the veterinary research institutes and university faculties of veterinary medicine in Africa. Several key discoveries were made at these institutions, including the isolation and propagation of African PPR virus isolates, notable amongst which was the Nigerian PPRV 75/1 that was used in the scientific study to understand the taxonomy, molecular dynamics, lineage differentiation of PPRV and the development of vaccine seeds for immunisation against PPR. African sheep and goat breeds including camels and wild ruminants are frequently infected, manifesting clinical signs of the disease, whereas cattle and pigs are asymptomatic but can seroconvert for PPR. The immunisation of susceptible sheep and goats remains the most effective and practical control measure against PPR. To carry out PPR vaccination in tropical African countries with a very high temperature, a thermostable vaccine using the rinderpest lyophilisation method to the attenuated Nigeria 75/1 PPR vaccine strain has been developed, which will greatly facilitate the delivery of vaccination in the control, prevention and global eradication of PPR. Apart from vaccination, other important questions that will contribute towards the control and prevention of PPR need to be answered, for example, to identify the period when a susceptible naïve animal becomes infectious when in contact with an infected animal and when an infectious animal becomes contagious.

Expression kinetics of ISG15, IRF3, IFNγ, IL10, IL2 and IL4 genes vis-a-vis virus shedding, tissue tropism and antibody dynamics in PPRV vaccinated, challenged, infected sheep and goats

Here, we studied the in vivo expression of Th1 (IL2 and IFN gamma) and Th2 (IL4 and IL10) - cytokines and antiviral molecules - IRF3 and ISG15 in peripheral blood mononuclear cells in relation to antigen and antibody dynamics under Peste des petits ruminants virus (PPRV) vaccination, infection and challenge in both sheep and goats. Vaccinated goats were seropositive by 9 days post vaccination (dpv) while in sheep idiosyncratic response was observed between 9 and 14 dpv for different animals. Expression of PPRV N gene was not detected in PBMCs of vaccinated and vaccinated challenged groups of both species, but was detected in unvaccinated infected PBMCs at 9 and 14 days post infection. The higher viral load at 9 dpi coincided with the peak clinical signs of the disease. The peak in viral replication at 9 dpi correlated with significant expression of antiviral molecules IRF3, ISG15 and IFN gamma in both the species. With the progression of disease, the decrease in N gene expression also correlated with the decrease in expression of IRF3, ISG15 and IFN gamma. In the unvaccinated infected animals ISG15, IRF3, IFN gamma and IL10 expression was higher than vaccinated animals. The IFN gamma expression predominated over IL4 in both vaccinated and infected animals with the infected exhibiting a stronger Th1 response. The persistent upregulation of this antiviral molecular signature - ISG15 and IRF3 even after 2 weeks post vaccination, presumably reflects the ongoing stimulation of innate immune cells.

Natural Peste des Petits Ruminants Virus Infection: Novel Pathologic Findings Resembling Other Morbillivirus Infections

The present study describes pathologic and virologic findings in 15 sheep and 6 goats that died of natural peste des petits ruminants virus infection in Turkey. Pathologic findings included erosiveulcerative stomatitis, fibrino-necrotic tracheitis, bronchointerstitial pneumonia, multifocal coagulation necroses in the liver, and severe lymphocytolysis in lymphoid tissues. Syncytial cells were conspicuous, especially in the oral mucosa, pulmonary alveoli, liver, and lymphoid tissues. In addition to the typical tissue distribution, eosinophilic intracytoplasmic and/or intranuclear inclusions were observed in epithelial cells lining the renal pelvis and abomasal mucosa. Immunolabeling of the viral antigen was observed in the kidney, brain, rumen, abomasum, heart, and myocytes of the tongue besides its more typical locations. In this study, we report and describe in detail the first peste des petits ruminants endemic in Kirikkale Province, Central Anatolia of Turkey. In conclusion, these previously unreported pathologic findings in natural peste des petits ruminants virus infection establish a basis for resemblance to other morbillivirus infections, such as canine distemper and distemper of sea mammals. Reverse transcriptase-polymerase chain reaction analyses indicated that the 448-bp genome fragment was amplified in 18 cases (18/21, 85.7%). Phylogenetic analysis showed that viruses belong to lineage 4 in the peste des petits ruminants virus common phylogenetic tree.

Abortion and various associated risk factors in small ruminants in Algeria

Identification of the causes of abortion among the huge population of small ruminants in Algeria (≈31 millions heads), is an important task for the control of livestock productivity and viability scourges to the small ruminants industry. Optimal production and utilization is constrained by a number of factors: disease, poor feeding and low management skills. Therefore, in the present study the prevalence of abortion in Algerian small ruminant's flocks was estimated and its possible association was correlated with infectious (PPR, BT and Brucellosis seropositivity) and managerial (flock size, grazing system, type of farming, and contact with other flocks) risk factors. The present study showed an overall flock prevalence of small ruminant's abortion as 75.33% (113/150) [95% CI 71.72-78.94%]. The risk factor analysis using multivariable logistic regression recognized the north-western and the steppe region as well as PPR positivity as a risk factor for abortion in Algerian small ruminant's flocks. The odds of flock abortion was 11.47 [95% CI 2.39-54.88; P=0.002] and 10.31 [95% CI 1.28-82.88; P=0.028] times higher in north-western and steppe regions respectively compared to other region. Also the presence of PPRV infection in small ruminant flocks amplified the odds by 6 times [95% CI 2.221-17.427; P=0.001].Surprisingly, the univariate analysis for the other risk factors associated with abortions in Algerian small ruminant flocks indicated no statistically significant links with bluetongue (P=1.000) and brucellosis seropositivity (P=0.334). Flock size (P=0.574), type of farming (P=0.443), grazing system (P=0.117) and contact with other flocks (P=0.245) was also not statistically significant. Our results revealed that abortion in small ruminants is a challenge to farmers and PPR was chiefly linked to it. Therefore an effective vaccination and control programme is advocated for small ruminants in Algeria.

Peste des petits ruminants virus tissue tropism and pathogenesis in sheep and goats following experimental infection

Peste des petits ruminants (PPR) is a viral disease which primarily affects small ruminants, causing significant economic losses for the livestock industry in developing countries. It is endemic in Saharan and sub-Saharan Africa, the Middle East and the Indian sub-continent. The primary hosts for peste des petits ruminants virus (PPRV) are goats and sheep; however recent models studying the pathology, disease progression and viremia of PPRV have focused primarily on goat models. This study evaluates the tissue tropism and pathogenesis of PPR following experimental infection of sheep and goats using a quantitative time-course study. Upon infection with a virulent strain of PPRV, both sheep and goats developed clinical signs and lesions typical of PPR, although sheep displayed milder clinical disease compared to goats. Tissue tropism of PPRV was evaluated by real-time RT-PCR and immunohistochemistry. Lymph nodes, lymphoid tissue and digestive tract organs were the predominant sites of virus replication. The results presented in this study provide models for the comparative evaluation of PPRV pathogenesis and tissue tropism in both sheep and goats. These models are suitable for the establishment of experimental parameters necessary for the evaluation of vaccines, as well as further studies into PPRV-host interactions.

Early events following experimental infection with Peste-Des-Petits ruminants virus suggest immune cell targeting

Peste-des-petits ruminants virus (PPRV) is a viral pathogen that causes a devastating plague of small ruminants. PPRV is an economically significant disease that continues to be a major obstacle to the development of sustainable agriculture across the developing world. The current understanding of PPRV pathogenesis has been heavily assumed from the closely related rinderpest virus (RPV) and other morbillivirus infections alongside data derived from field outbreaks. There have been few studies reported that have focused on the pathogenesis of PPRV and very little is known about the processes underlying the early stages of infection. In the present study, 15 goats were challenged by the intranasal route with a virulent PPRV isolate, Côte d'Ivoire '89 (CI/89) and sacrificed at strategically defined time-points post infection to enable pre- and post-mortem sampling. This approach enabled precise monitoring of the progress and distribution of virus throughout the infection from the time of challenge, through peak viraemia and into a period of convalescence. Observations were then related to findings of previous field studies and experimental models of PPRV to develop a clinical scoring system for PPRV. Importantly, histopathological investigations demonstrated that the initial site for virus replication is not within the epithelial cells of the respiratory mucosa, as has been previously reported, but is within the tonsillar tissue and lymph nodes draining the site of inoculation. We propose that virus is taken up by immune cells within the respiratory mucosa which then transport virus to lymphoid tissues where primary virus replication occurs, and from where virus enters circulation. Based on these findings we propose a novel clinical scoring methodology for PPRV pathogenesis and suggest a fundamental shift away from the conventional model of PPRV pathogenesis.

Tissue distribution and expression of signaling lymphocyte activation molecule receptor to peste des petits ruminant virus in goats detected by real-time PCR

In the present study, we investigated the tissue distribution and expression of signaling lymphocyte activation molecule (SLAM) in 40 tissues and organs of goats by real-time RT-PCR, in order to determine the role of these receptors in tissue tropism. SLAM mRNA was detected in all the samples investigated. The expression of SLAM mRNA was detected at high levels in spleen, mesenteric lymph node, hilar lymph node, mandibular lymph node, superficial cervical lymph node, nasal mucosa, duodenum, heart, gallbladder, thymus and blood; this is similar to the tissue tropism of peste des petits ruminant virus. However, it was surprising that expression of SLAM was low in lungs, colon and rectum which are the major sites of replication of PPRV. In addition, very low levels were detected in larynx, tongue and esophagus, which suggest the possible presence of an alternative receptor for PPRV. This study provided the first data on caprine SLAM for use in further studies of the pathogenesis of PPRV in goats.

Coagulation profile, haematological and biochemical changes in kids naturally infected with peste des petits ruminants

The aim of this study was to examine the coagulation profile in peste des petits ruminant (PPR) in kids. Five kids from a group of 150 animals (72 goats and 78 kids) were brought to the Veterinary Medical Teaching Hospital from a farm in Burdur province (Turkey) with nasal and ocular discharges and diarrhea. Fifteen goats and 41 kids had died due to diarrhea and three kids were presented to the Department of Pathology for diagnosis. Blood samples were taken from 12 ill animals (infected group) for haematological and biochemical analysis. In addition, five healthy kids were examined from another healthy flock (control group). Leukocyte and lymphocyte numbers of infected group showed significant declinations in comparison to control group (≤0.001). Haemorrhages in all organs of digestive system and small haemorrhagic areas in liver were caused to decrease in erythrocyte and haematocrit values (p ≤ 0.001) in infected group. Concentrations of blood urea nitrogen (BUN) (p ≤ 0.01) and creatinine (p ≤ 0.001) in infected group were significantly higher than control group. Compared to control group, significant increases were determined in serum concentrations of alkaline phosphatase (ALP) (p ≤ 0.01), aspartate aminotransferase (AST) (p ≤ 0.001) and alanine aminotransferase (ALT) (p ≤ 0.001) in the infected group. No significant differences were observed between the infected and control groups for serum gamma glutamyl-transferase (GGT) concentration value. In our study, thrombocytopenia (p ≤ 0.001) together with prolonged activated partial thromboplastin time (APTT; p ≤ 0.01) and prothrombin time (PT; p ≤ 0.001) may show that disseminated intravascular coagulopathy which can occur in kids with PPR.

An outbreak of peste des petits ruminants (PPR) in camels in the Sudan

In mid-August 2004, an outbreak of a previously unknown fatal disease of camels was reported to Kassala State veterinary authorities. Several areas in the state were visited during August-October 2004 to collect epidemiological data and specimens for diagnosis. Clinically the disease was characterized by sudden death of apparently healthy animals and yellowish and later bloody diarrhea and abortion. The disease outbreaks coincided with the seasonal movement of animals towards autumn green pasture. Death was always sudden and proceeded with colic and difficulty in respiration. Mortality rate ranged between 0% and 50% and vary in accordance with the area with a mean of 7.4%. More than 80% of deaths were in pregnant and recently-delivered she-camels. All age, sex and breed groups were affected but more than 50% of deaths were reported in adult animals in comparison to calves and young camels. The main post-mortem findings include lung congestion and consolidation, paleness and fragility of liver, enlarged lymph nodes and congestion and hemorrhage of small intestine and stomach. Agar gel diffusion test (AGDT), RT-PCR and virus isolation in cell culture gave positive results for peste des petits ruminants virus (PPRV), a virus belonging to the Morbillivirus, Genus, member of the family Paramyxoviridae. The effect of this new devastating disease on camel production in the affected area was discussed as well as proposals for future research.

Border disease virus (BDV) infections of small ruminants in Turkey: a new BDV subgroup?

Blood samples from sheep and/or goats from eight small ruminant flocks in the Turkish provinces of Aydin and Burdur were tested for the presence of Pestiviruses using an antigen-capture ELISA. From clinically affected animals, pathological and immunohistochemical findings were recorded. Post mortem examination of a virus-positive lamb showing abnormal fleece and paralysis of the hind legs revealed nonsuppurative meningoencephalomyelitis with hypomyelinogenesis. By immunohistochemistry Pestivirus antigen was detected in all parts of the brain including cerebellum, cerebral hemispheres and midbrain. Two Pestivirus isolates from a sheep and a goat kid, respectively, were isolated from samples that were positive in the antigen-capture ELISA. Genetic typing using the 5'-NTR (288bp) and N(pro) (738bp) showed that both were Border disease virus (BDV) isolates. By phylogenetic analysis, they formed a cluster clearly separated from the known clusters BDV-1 to BDV-6 and might therefore represent a new subgroup (BDV-7?). This is the first report confirming the occurrence and partial characterisation of BDV infection in small ruminants in Turkey.

Peste des petitis ruminants morbillivirus infection in lambs and young goats at Qassim region, Saudi Arabia

An outbreak of peste des petits ruminants (PPR) in lambs and young goats of Najdi breed of sheep and goats occurred during winter 2005 at Qassim region of central Saudi Arabia. The PPR infection was confirmed by demonstration of antibodies against the virus in the serum of clinically-ill young sheep and goats using competitive ELISA test. Clinical examination of infected animals showed fever, salivation, lacrimation, mucopurulent nasal discharge, difficult breathing and diarrhoea. The disease was particularly severe in the goats. Morbidity was about 20% and mortality was less than 3 percent. Autopsy showed necrotic and ulcerative lesions in the mouth, stomach and intestine. Mesenteric lymph nodes were swollen and congested. The lungs were patchy pneumonic mostly at the diaphragmatic and apical lobes. Liver and kidney lesions were seen in goats only and both organs were congested and necrotic. Histopathological examination revealed necrotic inflammation in the gastrointestinal tract. Intracytoplasmic viral inclusions were seen in the enterocytes of goats. Lung sections showed bronchopneumonia and syncytial and giant cells. The bronchial epithelium of goats had intracytoplasmic viral inclusions. Extensive coagulation necrosis, fatty degeneration and presence of intracytoplasmic viral inclusions were seen in hepatocytes and syncytial cells were evident in biliary epithelium of goats. Congestion, coagulation necrosis and syncytial cells were seen in the renal tubular epithelium of goats only. In a survey to determine the magnitude of the outbreak, PPR antibodies were evidenced in 363/996 (36.6%) sheep and 530/962 (55.1%) goats.

Concurrent Peste des Petits Ruminants Virus and Pestivirus Infection in Stillborn Twin Lambs

Concurrent infection with peste des petits ruminants virus (PPRV) and pestivirus was diagnosed in stillborn twin lambs. With the flock history, the findings of epidermal syncytial cells and necrotizing bronchitis/bronchiolitis prompted testing for PPRV infection, and PPRV antigen was detected by immunohistochemistry (IHC) in the skin, lungs, kidneys, rumen, and thymus. Macroscopic anomalies that were typical of border disease included scoliosis, brachygnathism, prognathism, arthrogryposis, hydranencephaly, cerebellar hypoplasia, and hairy fleece; pestiviral antigen was detected by IHC in the brain, liver, lungs, and kidneys. Tissues from both lambs were positive by reverse transcriptase-polymerase chain reaction (RT-PCR) for PPRV and pestivirus. To the authors' knowledge, PPR has not been reported previously as a congenital infection or in combination with pestiviral infection.

Involvement of morbilliviruses in the pathogenesis of demyelinating disease

Two members of the morbillivirus genus of the family Paramyxoviridae, canine distemper virus (CDV) and measles virus (MV), are well-known for their ability to cause a chronic demyelinating disease of the CNS in their natural hosts, dogs and humans, respectively. Both viruses have been studied for their potential involvement in the neuropathogenesis of the human demyelinating disease multiple sclerosis (MS). Recently, three new members of the morbillivirus genus, phocine distemper virus (PDV), porpoise morbillivirus (PMV) and dolphin morbillivirus (DMV), have been discovered. These viruses have also been shown to induce multifocal demyelinating disease in infected animals. This review focuses on morbillivirus-induced neuropathologies with emphasis on aetiopathogenesis of CNS demyelination. The possible involvement of a morbillivirus in the pathogenesis of multiple sclerosis is discussed.

Visceral leishmaniosis and parapoxvirus infection in a Mediterranean monk seal (Monachus monachus)

A Mediterranean monk seal was shown by immunohistochemical and polymerase chain reaction techniques to be dually infected with a Leishmania sp. and parapoxvirus. The pathological findings included a deep ulcer on the side of the head, ulcers on the gingival and inner aspect of the lower lip, enlarged lymph nodes and tonsils, and respiratory lesions (pulmonary consolidation, oedema, haemorrhages and emphysema; tracheal and bronchial congestion, exudates and haemorrhage). Amastigotes were demonstrated in macrophages in the lymph nodes and spleen, and intracytoplasmic inclusion bodies were observed in the tracheal and oral mucosa.

Peste des Petits Ruminants (PPR) Outbreak in Tajikistan

The occurrence of outbreaks of peste des petits ruminants (PPR) in three districts of Tajikistan is described. The causal strain (PPR Tajikistan) was characterized and the sequence of its N gene was compared with that of 43 other strains isolated since 1968 in Africa, the Middle East and Asia. The study demonstrated (1) the value of the N gene as a target in comparing isolates obtained over an extended period of evolution, and (2) that clustering was related to the geographical origin of strains.