Nutrition and food safety in Barotse, Zambia

Permanent URI for this collectionhttps://hdl.handle.net/10568/75830

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Antimicrobial resistant enteropathogenic Escherichia coli and Salmonella spp. in houseflies infesting fish in food markets in Zambia
(Journal Article, 2016-12-28) Songe, M.M.; Hang'ombe, M.B.; Knight-Jones, Theodore J.D.; Grace, Delia
Diarrhea is one of the most common diseases and is a leading cause of death in developing countries. This is often caused by contaminated food. Poor food hygiene standards are exacerbated by the presence of flies which can transmit a variety of infectious microorganisms, particularly through animal source foods. This fact becomes especially important in developing countries like Zambia, where fish is a highly valued source of protein. Our interest in this study was to identify if the flies that beset food markets in Zambia carry important pathogenic bacteria on their bodies, and subsequently if these bacteria carry resistance genes to commonly used antibiotics, which would indicate problems in eradicating these pathogens. The present study took into account fish vendors’ and consumers’ perception of flies and interest in interventions to reduce their numbers. We conducted semi-structured interviews with (1) traders (comprised of randomly selected males and females) and (2) consumers (including randomly selected males and females). Thereafter, we collected flies found on fish in markets in Mongu and Lusaka districts of Zambia. For the entire study, a total of 418 fly samples were analyzed in the laboratory and Salmonella spp. and enteropathogenic Escherichia coli were isolated from the flies. Further laboratory screening revealed that overall, 17.2% (72/418) (95% CI; 43.2%–65.5%) of total samples analyzed contained Extended-Spectrum Beta-Lactamase (ESBL)-producing E. coli. These significant findings call for a strengthening of the antibiotic administering policy in Zambia and the development of sustainable interventions to reduce fly numbers in food markets and improve food safety and hygiene.
Microbial contamination and hygiene of fresh cow’s milk produced by smallholders in western Zambia
(Journal Article, 2016-07-21) Knight-Jones, Theodore J.D.; Hang'ombe, M.B.; Songe, M.M.; Sinkala, Y.; Grace, Delia
A field study was performed to assess safety of smallholder fresh cow’s milk around Mongu, Western Province, Zambia. This involved observation and sampling of milk along the value chain from milking to point-of-sale and storage. Samples were collected from 86 cows, from 9 farmers, selling through two dairy cooperatives, with additional samples from informal markets. Production was very low; around one litre/day/cow and 10 L/day/herd. The milk was typically transported by bicycle in high ambient temperatures without refrigeration until reaching the point-of-sale (journey times of 30–120 min), where it was sold without pasteurisation despite milk-borne zoonoses being endemic (bovine tuberculosis (bTB) and Brucellosis). Although microbiological contamination was initially low, with geometric mean total bacterial count (TBC) of 425 cfu/mL (cfu = colony forming units) upon arrival at point-of-sale, poor hygiene led to high bacterial loads later on (geometric mean TBC > 600,000 cfu/mL after two days refrigeration), with almost all samples culture positive for Staphylococcus aureus and Escherichia coli. After milking, milk was kept for 100–223 min at temperatures favouring microbial growth (median 34 °C) and sold without a microbial kill step. In this situation limited variation in observed standards of milk hygiene had no significant effect on milk end-product bacterial counts. Options for refrigerated transport are limited. Pasteurisation at the cooperative should be investigated, as this would largely remove pathogenic microbes present in the milk whether resulting from cattle infection or poor hygiene during milking and transportation. As milk is also purchased directly from producers, on-farm milk heating options should also be assessed. Smallholders may benefit from access to national markets by providing milk to large dairies, which have systems for ensuring safety. However, this requires significant investment and an increased and more consistent supply of milk; and many consumers, unable to afford milk sold through formal sectors, would not benefit.
Rapid assessment of safety of informal fish value chains in the Western Province of Zambia, June–August 2014
(Report, 2014-08-30) Soto, R.A.
Fish provide an important source of income and protein to poor households. Consumption of fish within the Western province, Zambia is estimated at about five times the national average. Fishers and traders in the Barotse flood plain dry (sun-dry or smoke-dry) part of their fish catches. In the fish value chain, this high value, perishable resource gets exposed to food safety hazards and becomes a potential source of food-borne disease. A rapid qualitative assessment of the safety of the fish value chain in the Western Province of Zambia was undertaken with the use of an adapted rapid integrated assessment toolkit that focuses on the food safety hazards at each link in the chain, developed by the International Livestock Research Institute (ILRI) and with guidance from WorldFish. The assessment was carried out by conducting 55 interviews with key informants in 14 sites in the Mongu, Kalabo, Lukulu and Senanga districts of Western Province and the application of a checklist of marketplace conditions. Traders were the main source of information, although fishers and consumers were also interviewed. This is part of ILRI work on moving food safety to scale through value chains, within the Aquatic Agricultural Systems (AAS) and the Agriculture for Nutrition and Health (A4NH) programs of the CGIAR consortium. A number of food safety issues along the value chain have been identified, such as the application of chemicals intended for preservation of grains on dry fish; the use of poisons to capture fish; growth of mold on fish that have over-stayed and the lack of well-equipped market places. Recommendations from this study include: Laboratory analyses of fish for mycotoxins and possibly chemical residues, identification and evaluation of the health hazards and risks associated with the use of natural herbs to capture fish, education on, and enforcement of the proper fishing methods, key investments in market places (such as introduction of refrigeration facilities and netting to avoid flies, dust and human contact) and the promotion of alternative methods of preserving the fish, such as salting.
Is Barotse fish safe? Rapid assessment of safety of informal fish value chains in Western Province, Zambia
(Presentation, 2014-08) Soto, R.A.
Food safety in Western Province, Zambia: Field visits and scoping mission
(Report, 2015-02) International Livestock Research Institute
Food safety advisory meeting report
(Report, 2016-03) Songe, M.; Knight-Jones, Theodore J.D.
ILRI in Zambia and sub-Saharan Africa: Food safety, zoonoses and animal health
(Presentation, 2015-06-18) Knight-Jones, Theodore J.D.
A thicker chorion gives ova of Atlantic salmon (Salmo salar L.) the upper hand against Saprolegnia infections
(Journal Article, 2016-07) Songe, M.M.; Willems, A.; Sarowar, M.N.; Rajan, K.; Evensen, A.; Drynan, K.; Skaar, I.; West, P. van
Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.
Saprolegnia diclina IIIA and S. parasitica employ different infection strategies when colonising eggs of Atlantic salmon, Salmo salar L.
(Conference Paper, 2015-09) Songe, M.; Willems, A.; Wiik-Nielsen, J.; Thoen, E.; Evensen, A.; West, P. van; Skaar, I.
In this study, we addressed the morphological changes of eyed eggs of Atlantic salmon, Salmo salar L. infected with Saprolegnia from a commercial hatchery and after experimental infection. Eyed eggs infected with Saprolegnia spp. from 10 Atlantic salmon females were obtained. Egg pathology was investigated by light and scanning electron microscopy. Eggs from six of ten females were infected with S. parasitica, and two females had infections with S. diclina clade IIIA; two Saprolegnia isolates remained unidentified. Light microscopy showed that S. diclina infection resulted in the chorion in some areas being completely destroyed, whereas eggs infected with S. parasitica had an apparently intact chorion with hyphae growing within or beneath the chorion. The same contrasting pathology was found in experimentally infected eggs. Scanning electron microscopy revealed that S. parasitica grew on the egg surface and hyphae were found penetrating the chorion of the egg, and re-emerging on the surface away from the infection site. The two Saprolegnia species employ different infection strategies when colonizing salmon eggs. Saprolegnia diclina infection results in chorion destruction, while S. parasitica penetrates intact chorion. We discuss the possibility that these infection mechanisms represent a necrotrophic (S. diclina) versus a facultative biotrophic strategy (S. parasitica).
Saprolegnia diclina IIIA and S. parasitica employ different infection strategies when colonizing eggs of Atlantic salmon, Salmo salar L
(Journal Article, 2016-03) Songe, M.M.; Willems, A.; Wiik-Nielsen, J.; Thoen, E.; Evensen, A.; West, P. van; Skaar, I.
Here, we address the morphological changes of eyed eggs of Atlantic salmon, Salmo salar L. infected with Saprolegnia from a commercial hatchery and after experimental infection. Eyed eggs infected with Saprolegnia spp. from 10 Atlantic salmon females were obtained. Egg pathology was investigated by light and scanning electron microscopy. Eggs from six of ten females were infected with S. parasitica, and two females had infections with S. diclina clade IIIA; two Saprolegnia isolates remained unidentified. Light microscopy showed S. diclina infection resulted in the chorion in some areas being completely destroyed, whereas eggs infected with S. parasitica had an apparently intact chorion with hyphae growing within or beneath the chorion. The same contrasting pathology was found in experimentally infected eggs. Scanning electron microscopy revealed that S. parasitica grew on the egg surface and hyphae were found penetrating the chorion of the egg, and re-emerging on the surface away from the infection site. The two Saprolegnia species employ different infection strategies when colonizing salmon eggs. Saprolegnia diclina infection results in chorion destruction, while S. parasitica penetrates intact chorion. We discuss the possibility these infection mechanisms representing a necrotrophic (S. diclina) vs. a facultative biotrophic strategy (S. parasitica).
Impact of neglected diseases on animal productivity and public health in Africa
(Presentation, 2015-02-17) Grace, Delia; Songe, M.; Knight-Jones, Theodore J.D.
Animal diseases have important impacts on animal productivity and welfare, and on human health and wellbeing. A survey, commissioned by the OIE, was conducted to generate information on the impact of animal diseases in OIE Member Countries in Africa. This identified priority animal diseases according to their impacts: for instance, epidemic diseases affect trade and assets, endemic diseases affect livestock and fish productivity, zoonoses and food-borne diseases are a threat to human health and emerging diseases can shock economies. The survey identified animal diseases that most impact on different aspects of national economies. It found that state Veterinary Services rank human development impacts of disease as especially important when deciding on disease priorities. For most diseases, respondents reported that control is only fair or poor. However, good progress is reported in developing priority disease lists and contingency plans and inclusion of both public and private veterinary services in vaccination. Overall, animal diseases were seen to be increasing (44% of the diseases assessed) or static (also 44%); this is another indicator that investments in better control are required. Disease increase was the result of a number of drivers, the most important of which were climate change, trade, population growth and livestock intensification. In terms of disease prevalence, respondents reported that many important diseases were common. They also reported that treatments were commonly applied. These are both indicators of the high impacts of disease. Only a minority of animals are slaughtered in approved abattoirs, a situation that poses a risk to human health. Respondents provided estimates of disease parameters, which were used to generate a preliminary estimate of some economic impacts of animal disease on the livestock sector. The 35 priority diseases were estimated to cost nearly USD 9 billion a year, equivalent to 6% of the total value of the livestock sector in Africa. Most of this cost was from the death of adult animals, followed by the death of young animals, the cost of vaccination campaigns and the cost of treatment. Microbial hazards, many of which are zoonotic and/or associated with food of animal origin were seen to be of great importance to human health and a source of economic losses. Antimicrobial resistance, linked to the use of antibiotics in agriculture, was also a cause for concern in most countries. Better disease reporting can lead to a better understanding of the impacts of animal diseases. Respondents put forward suggestions on how this could be achieved. Suggestions as to how the OIE could best support the control of animal diseases were also put forward.

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