Discussion on a selection of key scientific articles


Descriptive survey of peste des petits ruminants and contagious caprine pleuropneumonia outbreaks in traditional goat flocks in Southern Tanzania: Producers' concerns, knowledge and attitudes


2015, Livestock Research for Rural Development, 27 (4), Mbyuzi, A.O., Komba, E.V.G., Cordery-Cotter, R., Magwisha, H.B., Kimera, S.I., Kambarage, D.M., 2015.

Farming in sub-Saharan Africa is subject to a large number of constraints, such as feed and water resources, poor animal husbandry, poor marketing, and the high burden of disease.  This restricts the contribution to household economies.  Diseases such as Peste de Petits Ruminants (PPR) and Contagious Caprine Pleuropneumoniae (CCPP) have become of increased concern in recent years due to important drivers in disease dynamics such as high morbidity and mortality, uncontrolled movement of animals, and communal grazing. The continued presence of these diseases is likely to cause a serious threat to resource-poor farmers in southern Tanzania.

The study was designed to evaluate concerns and attitudes towards these diseases as an entry point to community engagement.  A questionnaire-based survey of smallholders in southern Tanzania was conducted during January 2013.  This involved 200 small ruminant producers from 4 randomly selected wards in the Tandahimba district, the district being chosen because of the high number of small ruminants, although 59 producers refused to participate.  The respondents represented 23.2% of the producers in the area.  The questionnaire was completed during face-to-face interviews of approximately 1 hour duration.

Animal diseases were recognized as the major constraint for these farmers, significantly higher than any other constraints such as feed resources (3.3%) and water scarcity (0.8%).  Of those indicating that disease was the major constraint, 73% identified PPR and CCPP as the most important.  Goats were reported as having significantly higher morbidity and mortality than sheep.

There is some evidence that attitudes to these diseases have changed since introduction to the country and there is increased pressure from consumers for both ante-mortem and postmortem inspections.  However, vaccinating programmes initiated by the government have not controlled disease outbreaks in the district and this has led to skepticism regarding vaccine usage.  In contrast, a different ward had better vaccination rates and also better success in preventing outbreaks.  This could suggest that the problems lie with implementation of the campaign rather than with the vaccine itself.

Key Thoughts:  Disease is often identified as a major limitation on smallholders in Africa and a reason for farmers failing to escape the poverty trap.  Peste de Petits Ruminants and Contagious Caprine Pleuropneumoniae were identified as being the most important of these diseases and small ruminant animal keepers have a serious challenge in the face of economically devastating diseases.  The smallholders who refused to participate in the study reportedly did so owing to a perceived failure of vaccination efforts, and this supports the importance of ensuring that vaccination campaigns are well organized and produce positive results in order to avoid negative feedback and loss of engagement.


WHO Regional Office for Europe overview on avian influenza for public health professionals, WHO, 2015.


World Health Organization. WHO Regional Office for Europe overview on avian influenza for public health professionals. Published March 2015. Accessed June 2015.

Avian influenza viruses are grouped according to the disease observed in chickens. High pathogenicity Avian Influenza (HPAI) causes severe disease and high death rates, while low pathogenicity Avian Influenza (LPAI) often causes no more than subclinical infection. While person-to-person spread is not common, the potential to become pandemic needs an intersectoral approach.  The report published by the WHO during the last quarter summarises information on avian influenza viruses known to infect humans.

H5, H7 and H9 subtypes have been known to infect people, with other subtypes also occurring on a sporadic basis.  H5N1 alone has caused more than 780 human cases since it re-emerged in 2003, and it results in a severe, highly fatal disease.  However, it is important to note that in humans, LPAI subtypes can also cause disease. For instance, H7N9 also causes a severe, highly fatal disease and has been diagnosed in over 600 cases.  In recent years new subtypes are being found in Europe and North America.

A major concern with LPAI viruses is that they generally cause subclinical disease in poultry, despite posing risk of severe disease in humans.  This means that they can be difficult to detect until causing human disease.  Even when not causing significant disease in humans, LPAI subtypes such as H9N2 are important for the evolution of the virus and genetic reassortment with other subtypes, leading to new threats.

Although human HPAI cases are mainly seen in Asia, China and Egypt, there have now been reports in all six WHO regions.  Epidemiological and virological investigations are still ongoing, but point to environmental and social factors (rather than any major genetic changes) as the reason behind the high numbers of recent cases.

During the first half of 2015 there have been a large number of cases in poultry of both LPAI and HPAI, and a number of these have been H5 subtypes.  Geographical spread of these outbreaks has reached from Asia, across Europe, and to North America.  Importantly, the H5N1 reassortment in North America is genetically different as compared to viruses identified elsewhere.  The evidence generally points towards wild avian species as being the likely source of infection.

The report contains key advice for national authorities, which recognizes that to decrease the risk of disease in humans it is also necessary to control the disease in animals.  Prevention and control need to be approached by both veterinary and human health authorities in a collaborative and coordinated manner.  This should include information-sharing, and communication routes should either be established or strengthened.

For human health, surveillance, diagnostics and treatment are all highlighted.  While protective clothing for those working on, or in contact with, infected birds and affected farms is recommended, this does not negate the requirement for surveillance of these persons, and they should be monitored for signs of influenza like illnesses (ILI) or acute respiratory infections.  Good communication is important to ensure local clinicians and health workers are aware that viruses have been identified.  If symptoms do occur, swabs should be taken within the first week and submitted for PCR testing.  Samples that are either unsubtypable or for which an avian subtype has been identified should be sent to a WHO Collaborating Centre.  In suspected cases, antiviral drugs, in particular oseltamivir, should be subscribed as soon as possible.

Key Thoughts:  Avian influenza is a constant threat; new human and poultry cases are occurring, and the virus is undergoing reassortment on a regular basis.  In order to reduce the risks, it is important that human and veterinary health professionals work together on multi-hazard plans so as to be ready to respond to public health threats when they arise.  It is important not to ignore low pathogeicity avian influenza viruses as these can cause clinical, (and sometimes severe to fatal), disease in humans, despite causing only subclinical disease in poultry.


Impact of foot-and-mouth disease on mastitis and culling on a large-scale dairy farm in Kenya.

veterarians tending to dairy cow

Nick Lyons examining cattle in Kenya for his PhD. Credit: With grateful thanks to Nick Lyons and the EuFMD.

Veterinary Research , 46 (1), art. no. 41,  Lyons, N.A., Alexander, N., Stärk, K.D.C., Dulu, T.D., Rushton, J., Fine, P.E., 2015.

Firstly, we must admit to a vested interest in this paper, as MSD Animal Health sponsored the author and his PhD.  That said, this represents important work on the real impact of FMD in cattle.

Although FMD is recognized as causing severe economic losses when introduced to previously disease-free countries, the impact in endemic countries is less well understood.  It has been estimated that FMD causes losses of $11 billion a year in endemic countries, but it is likely that the effects of production loss are underestimated, as they are based on incomplete data.  This paper follows the impact of an SAT2 outbreak in a large-scale dairy farm in Kenya over a 12-month period.  The farm normally had approximately 600 cattle, 100 sheep and 300 goats.  Grazing groups for the cattle depended on a number of factors.  Farm income was mainly through milk sales and cattle sales.

In 2012 an outbreak of FMD, serotype SAT2, was detected.  This was the first time the disease had been seen on the farm since 2004.  All cattle were regularly vaccinated with a quadrivalent vaccine (O, A, SAT1, SAT2).  While daily cases were recorded, not all animals were examined due to the high proportion of animals affected (400 animals, or 62.1% of the herd).  No cases were observed among the small ruminants on the farm.  The outbreak lasted around a month.  Records were analysed for the subsequent year for the development of clinical mastitis, or culling from the herd.

Examination of the data shows evidence for a difference in culling between those animals contracting FMD and those that remained free of disease, with the risk growing larger over the 12 months post disease; although this became less clear when possible confounders were taken into consideration.  One issue here was that older animals were also at greater risk of FMD, and are also naturally at higher risk of culling.  There were also differences for development of mastitis, but these were most obvious in the first two months after the outbreak.  During the study period 76 animals were culled and, of those 18 months or older at the time of the outbreak, 63 developed clinical mastitis. 

This study was on a large-scale dairy farm, the set-up still being in the minority in Kenya.  Care must be taken extrapolating the data to the overall cattle population in Africa.  However, there are similarities to the local smallholder population. For instance, the most common cattle breed in Kenya is the Holstein-Friesian.  Additionally, the feeding regime was not too different from that used in organized smallholder regions.  These results can therefore be used to help inform decisions in the field and go some way towards redressing the imbalance between assumptions and field data. 

Key thoughts:  This study is unusual in trying to follow the impact of FMD over time and analyzing what happens for the 12 months post outbreak.  The indications are that there are more mastitis cases in animals affected with FMD for a few months after disease, and that there is an increased risk of culling over the subsequent year.  Of additional interest is the fact that previous studies had indicated that vaccination in the region provided little to no clinical protection from disease, which may raise questions about the quality of vaccine in use.  The results from this work may go towards helping improve decisions on FMD control and strategy.


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