Discussion on a Selection of Key Scientific Articles

 

Challenges of pastoral cattle production in a sub-humid zone of Nigeria.

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Suleiman A, Jackson EL, Rushton J. Trop Anim Health Prod. 2015;47(6):1177-1185.

Key Thoughts: At a national level foot and mouth disease is important for developing countries, often affecting the ability to trade with wealthier countries and thus limiting their ability to move out of the poverty trap.  However, for the individual livestock owner FMD may not be the highest priority.  This leads to conflict between government and community. 

It is important to understand all the challenges to animal production and to create solutions that address these issues as a whole so that all benefit.  Disease was only ranked fourth in the list of concerns, but we wonder how much of that was driven by the poor access to veterinary care for their animals. Pastoralists admitted that outbreaks were often not reported; instead, “distress sales” of sick animals were conducted to minimize losses.  This is concerning because it means that disease epidemiology is poorly understood in the region, while the sales will allow greater spread. 

Article review:  Data from the FAO indicates that there are approximately 20 million cattle in Nigeria and 80% of these are kept in some sort of pastoral smallholder system.  Pastoralism is  practiced in dry areas where crop growing is limited.  Cattle provide food, social satisfaction, fuel and farm power, as well as act as a safety net against disaster.

Livestock can play a major role in the relief of poverty as well as provide food security.  However, current cattle systems in Nigeria have not adapted well to changes in other farming practices and there are often tensions between pastoralists and crop farmers.  Disease has also been identified as a major limiting factor on productivity.

This study adopted a framework of participatory epidemiology, involving the community in identifying their problems.  Semi-structured interviews with pastoralists were used to provide the data, and the study was conducted in Kaduna State, a strategic zone for livestock production.  In total, 86 pastoralists were interviewed in 10 focus groups. The local language was used and then subsequently translated into English.

Disease only ranked fourth in the list of husbandry problems.  The conversion of cattle routes into cropland had the most impact, followed by cattle rustling and scarcity of water.  Rustling has become a growing problem, previously only being an occasional happening.  It is not clear why this has increased, but it may negatively impact on disease management and productivity.  Although disease was recognized as causing serious losses, participants had poor access to veterinary services, both because of distance to clinics and the costs of treatment.  Water scarcity was identified as a reason for the persistence of contagious disease, as animals were sharing limited resources.

Within the disease sector, trypanosomiasis was identified as having the greatest impact on livelihoods while also being the second most prevalent disease.  The other key diseases were contagious bovine pleuropneumonia, fascioliasis and foot and mouth disease (FMD).  FMD ranked fourth for impact and third for prevalence.  While CBPP was identified as having a large impact because it causes more losses than other disease and has prolonged morbidity, it is not as prevalent and not always a problem.

 

Genetic characterization of peste des petits ruminants virus, Turkey, 2009-2013.

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Şevik M, Sait A. Res Vet Sci. 2015;101:187-195.

Key Thoughts:  PPR has been present in Turkey for approximately 15 years.  The highest seroprevalence is in the Southeast and East and is attributed to illegal trade.  Much as with foot and mouth disease (FMD), this presents a risk to the EU as there is strong movement of ruminants from the East to the West of the country. The sequences in this study were all closely related and were clustered within lineage IV.   Vaccination appears to have been very effective at reducing the level of disease in the country.  It appears that vaccine strain can protect against multiple lineages.

Article review:  PPR is caused by a morbillivirus and is closely related to rinderpest, canine distemper and measles.  The virus has a single strand RNA genome.  There is just one serotype with four lineages with different geographical spread.

Outbreaks of PPR have occurred in Turkey since 1999 when it was first officially reported in the country, and it has been found in both Anatolia and Thrace.  This study aimed to use phylogenetic analysis to provide insights into the origin and spread of the PPR virus circulating in Turkey.

782 organ samples from unvaccinated animals with signs of PPR from various regions in Turkey were analysed.  Virus RNA was detected in samples from 62 animals.  RT PCR was used on the majority of samples although virus isolation in cell culture was attempted in some cases.  PCR material was sequenced at least twice.

F gene nucleotide and N gene amino acid sequences revealed a homology of between 97-100%, both with other isolates in the study and also previously characterized isolates.  F gene sequences had a 92-93% similarity with the reference vaccine, lineage II Nig 75/1, while N gene sequences showed 88-91% homology.  The isolates clustered with isolates from the Middle East.

The seroprevalence of PPR in Turkey has varied from 8.39% to 47.17% in different studies.  The highest seroprevalence rates are found in the Southeast, bordering Syria and Iraq, and East Anatolia, bordering Iran.  Illegal trade is the likely explanation for the higher seroprevalence in these regions.  Although the prevalence falls moving westward, PPRV nucleic acid was still detected in 31.25% of the animals tested in the Mediterranean region.  This is consistent with the movement of ruminants from Eastern Turkey to Western and Central Anatolia.

PPR is endemic in Turkey and mass vaccination is used to control the disease.  All newborn lambs and kids over the age of two months are vaccinated.  The mass vaccination programmes started in 2010 and the percentage of animals positive for PPR has fallen every year since then.  In addition clinical cases have fallen.  The virus was detected at a higher rate in young animals, which is consistent with reports of high morbidity and mortality in young animals.  There was also evidence that PPR was responsible for abortions.

The characterization of the virus from samples indicates that the virus in Turkey is grouped in lineage IV along with viruses from Egypt, Iraq, Iran, China, Nepal, Bangladesh, India, Kuwait, Saudi Arabia, Pakistan and Morocco.  It is likely that the source of the infection is a neighbouring country.

 

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