An appraisal of the indigenous chicken market in Tanzania and Zambia. Are the markets ready for improved outputs from village production systems?

Traditional or village poultry, consisting primarily of indigenous chickens, make up over 80% of poultry in Africa. Most are kept as small flocks in free-ranging, scavenging, low input production systems. They provide vital nutritional and financial needs especially for children, women of reproductive age, people with HIV/AIDS and the poor. Poultry meat and eggs provide animal source protein and essential micronutrients which improves growth and cognitive development in children. While productivity of indigenous chickens is low due to uncontrolled disease and an unreliable scavenging resource base, the minimal inputs result in a high benefit-cost ratio. By increasing supplementary feeding through improved crop yields and improving disease control through vaccination, a higher number of chickens of greater bodyweight will be available to market. An appraisal of the indigenous chicken market in Tanzania and Zambia was conducted to identify the key individuals (including gender imbalances), market channels, commercialisation margins, market trends and competition from exotic, commercial chickens (broilers and spent layers). Consumers preferred indigenous chickens and urban consumers paid their significantly higher price, which resulted from the accumulative costs of intermediary traders’ fees, transport costs and market fees. Commercial chickens in urban markets sold at a lower price but were vulnerable to fluctuating costs of high inputs. Indigenous chicken producers’ margins were favourable enough to suggest that some additional costs were sustainable, provided the off take channels and consumer confidence is sustained. Markets for indigenous chickens were informal and consequently, their response to increased production may be unpredictable

Bovine tuberculosis in east Africa

The zoonotic Mycobacterium bovis is a pathogen of significance in the dairy industry in many parts of the world. Although the pathogen primarily affects cattle, it has a wide host range including humans. A cross-sectional study was carried out in three agro-ecological zones of Tanzania, namely the southern highlands zone (SHZ), eastern zone (EZ) and northern zone (NZ), to examine the status of the disease in cattle, in order to inform control measures. A total of 391, 169 and 401 cattle were tested for bovine tuberculosis (bTB) in the SHZ, EZ and NZ respectively using the Single Intradermal Comparative Cervical Tuberculin Test (SICTT). Results showed that the prevalence of bTB was higher (P<0.05) in EZ 2.37% (n = 169) compared to SHZ 1.3% (n=391) and NZ, where no positive result was recorded (n = 401). Thirty three cattle from SHZ and seven from EZ showed inconclusive results. In Kenya, 625 cattle from four sites within agro-pastoral and pastoral production systems were tested. In one area of Mwingi County, eastern Kenya, all the 161 cattle tested negative; while in the other three sites of Migori, in Nyanza, West Pokot and Laikipia in the Rift Valley, prevalence of 4-6% was obtained with SICTT. Bovine TB occurs in the region and may pose a public health threat through occupational activities and/or consumption of animal products, especially since no obvious clinical signs were observed in positive animals. Policy issues on how to deal with positive cases, creation of awareness on this important zoonotic disease, and a simple test to quickly identify sick animals in the field require urgent attention.La bact\ue9rie zoonotique Mycobacterium bovis est un agent pathog\ue8ne d\u2019importance dans l\u2019industrie laiti\ue8re partout dans le monde entier. Bien que l\u2019agent pathog\ue8ne affecte essentiellement les bovins, il peut infecter une large range d\u2019h\uf4tes l\u2019homme y compris. Une \ue9tude transversale a \ue9t\ue9 r\ue9alis\ue9e dans trois zones agro-\ue9cologiques de la Tanzanie, notamment la zone Sud (SHZ), la zone Est (EZ) et la zone Nord (NZ), afin d\u2019examiner la pr\ue9valence de cette maladie chez les bovins, en vue de d\ue9finir des mesures pour son contr\uf4le. Au total, 391, 169 et 401 bovins ont \ue9t\ue9 testes pour la tuberculose bovine (bTB) respectivement dans le SHZ, EZ et NZ. Le test Intradermique Comparatif a la Tuberculine Cervicale (SICTT). Les r\ue9sultats ont montr\ue9 que la pr\ue9valence de bTB \ue9tait \ue9lev\ue9e (p<0.05) en EZ 2.37% (n = 169) comparativement \ue0 SHZ 1.3% (n=391) et NZ, ou aucun cas positif n\u2019a \ue9t\ue9 enregistre (n = 401). Trente-trois bovins de SHZ et 7 de EZ ont montre des r\ue9sultats non conclusifs. Au Kenya, 625 bovins provenant de quatre sites au sein des syst\ue8mes de production agro-pastorale et pastorale ont \ue9t\ue9 testes. Dans une zone de Mwingi a l\u2019Est du Kenya, tous les 161 bovins ont \ue9t\ue9 testes n\ue9gative; tandis que dans les trois autres sites de Migori, en Nyanza, West Pokot et Laikipia dans la vall\ue9e du Rift, la pr\ue9valence \ue9tait de 4-6% avec le test SICTT. La tuberculose bovine est pr\ue9sent\ue9 dans la r\ue9gion et peut engendrer des menaces de sante publique au travers des activit\ue9s d\u2019\ue9levage et la consommation de viandes infect\ue9es, surtout qu\u2019aucun signe Clinique \ue9vident n\u2019a \ue9t\ue9 observe chez les animaux d\ue9pist\ue9s positifs. Il est important et urgent de d\ue9finir des mesures de gestion des cas positifs, de sensibiliser les populations sur les risques probables et de rendre disponibles des kits de tests rapides permettant d\u2019identifier \ue0 temps les animaux atteints

The chicken or the egg? Exploring bi-directional associations between Newcastle disease vaccination and village chicken flock size in rural Tanzania

Newcastle disease (ND) is a viral disease of poultry with global importance, responsible for the loss of a potential source of household nutrition and economic livelihood in many low-income food-deficit countries. Periodic outbreaks of this endemic disease result in high mortality amongst free-ranging chicken flocks and may serve as a disincentive for rural households to invest time or resources in poultry-keeping. Sustainable ND control can be achieved through vaccination using a thermotolerant vaccine administered via eyedrop by trained "community vaccinators". This article evaluates the uptake and outcomes of fee-for-service ND vaccination programs in eight rural villages in the semi-arid central zone of Tanzania. It represents part of an interdisciplinary program seeking to address chronic undernutrition in children through improvements to existing poultry and crop systems. Newcastle disease vaccination uptake was found to vary substantially across communities and seasons, with a significantly higher level of vaccination amongst households participating in a longitudinal study of children's growth compared with non-participating households (p = 0.009). Two multivariable model analyses were used to explore associations between vaccination and chicken numbers, allowing for clustered data and socioeconomic and cultural variation amongst the population. Results demonstrated that both (a) households that undertook ND vaccination had a significantly larger chicken flock size in the period between that vaccination campaign and the next compared with those that did not vaccinate (p = 0.018); and (b) households with larger chicken flocks at the time of vaccination were significantly more likely to participate in vaccination programs (p < 0.001). Additionally, households vaccinating in all three vaccination campaigns held over 12 months were identified to have significantly larger chicken flocks at the end of this period (p < 0.001). Opportunities to understand causality and complexity through quantitative analyses are limited, and there is a role for qualitative approaches to explore decisions made by poultry-keeping households and the motivations, challenges and priorities of community vaccinators. Evidence of a bi-directional relationship, however, whereby vaccination leads to greater chicken numbers, and larger flocks are more likely to be vaccinated, offers useful insights into the efficacy of fee-for-service animal health programs. This article concludes that attention should be focused on ways of supporting the participation of vulnerable households in ND vaccination campaigns, and encouraging regular vaccination throughout the year, as a pathway to strengthen food security, promote resilience and contribute to improved human nutrition

Infection, colonization and shedding of Campylobacter and Salmonella in animals and their contribution to human disease: A review

Livestock meat and offal contribute significantly to human nutrition as sources of high‐quality protein and micronutrients. Livestock products are increasingly in demand, particularly in low‐ and middle‐income settings where economies are growing and meat is increasingly seen as an affordable and desirable food item. Demand is also driving intensification of livestock keeping and processing. An unintended consequence of intensification is increased exposure to zoonotic agents, and a contemporary emerging problem is infection with Campylobacter and Salmonella spp. from livestock (avian and mammalian), which can lead to disease, malabsorption and undernutrition through acute and chronic diarrhoea. This can occur at the farm, in households or through the food chain. Direct infection occurs when handling livestock and through bacteria shed into the environment, on food preparation surfaces or around the house and surroundings. This manuscript critically reviews Campylobacter and Salmonella infections in animals, examines the factors affecting colonization and faecal shedding of bacteria of these two genera as well as risk factors for human acquisition of the infection from infected animals or environment and analyses priority areas for preventive actions with a focus on resource‐poor settings

Genetic and antigenic variation of the bovine tick-borne pathogen Theileria parva in the Great Lakes region of Central Africa

BACKGROUND : Theileria parva causes East Coast fever (ECF), one of the most economically important tick-borne diseases of cattle in sub-Saharan Africa. A live immunisation approach using the infection and treatment method (ITM) provides a strong long-term strain-restricted immunity. However, it typically induces a tick-transmissible carrier state in cattle and may lead to spread of antigenically distinct parasites. Thus, understanding the genetic composition of T. parva is needed prior to the use of the ITM vaccine in new areas. This study examined the sequence diversity and the evolutionary and biogeographical dynamics of T. parva within the African Great Lakes region to better understand the epidemiology of ECF and to assure vaccine safety. Genetic analyses were performed using sequences of two antigencoding genes, Tp1 and Tp2, generated among 119 T. parva samples collected from cattle in four agro-ecological zones of DRC and Burundi. RESULTS : The results provided evidence of nucleotide and amino acid polymorphisms in both antigens, resulting in 11 and 10 distinct nucleotide alleles, that predicted 6 and 9 protein variants in Tp1 and Tp2, respectively. Theileria parva samples showed high variation within populations and a moderate biogeographical sub-structuring due to the widespread major genotypes. The diversity was greater in samples from lowlands and midlands areas compared to those from highlands and other African countries. The evolutionary dynamics modelling revealed a signal of selective evolution which was not preferentially detected within the epitope-coding regions, suggesting that the observed polymorphism could be more related to gene flow rather than recent host immune-based selection. Most alleles isolated in the Great Lakes region were closely related to the components of the trivalent Muguga vaccine. CONCLUSIONS : Our findings suggest that the extensive sequence diversity of T. parva and its biogeographical distribution mainly depend on host migration and agro-ecological conditions driving tick population dynamics. Such patterns are likely to contribute to the epidemic and unstable endemic situations of ECF in the region. However, the fact that ubiquitous alleles are genetically similar to the components of the Muguga vaccine together with the limited geographical clustering may justify testing the existing trivalent vaccine for cross-immunity in the region.Additional file 1: Table S1. Cattle blood sample distribution across agroecological zones.Additional file 2: Table S2. Nucleotide and amino acid sequences of Tp1 and Tp2 antigen epitopes from T. parva Muguga reference sequence.Additional file 3: Table S3. Characteristics of 119 T. parva samples obtained from cattle in different agro-ecological zones (AEZs) of The Democratic Republic of Congo and Burundi.Additional file 4: Figure S1. Multiple sequence alignment of the 11 Tp1 gene alleles obtained in this study.Additional file 5: Table S4. Estimates of evolutionary divergence between gene alleles for Tp1 and Tp2, using proportion nucleotide distance.Additional file 6: Table S5. Tp1 and Tp2 genes alleles with their corresponding antigen variants.Additional file 7: Table S6. Amino acid variants of Tp1 and Tp2 CD8+ T cell target epitopes of T. parva from DRC and Burundi.Additional file 8: Figure S2. Multiple sequence alignment of the 10 Tp2 gene alleles obtained in this study.Additional file 9: Table S7. Distribution of Tp1 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.Additional file 10: Table S8. Distribution of Tp2 gene alleles of T. parva from cattle and buffalo in the sub-Saharan region of Africa.Additional file 11: Figure S3. Neighbor-joining tree showing phylogenetic relationships among 48 Tp1 gene alleles described in Africa.Additional file 12: Figure S4. Phylogenetic tree showing the relationships among concatenated Tp1 and Tp2 nucleotide sequences of 93 T. parva samples from cattle in DRC and Burundi.This study is part of the PhD work supported by the University of Namur (UNamur, Belgium) through the UNamur-CERUNA institutional PhD grant awarded to GSA for bioinformatic analyses, interpretation of data and manuscript write up in Belgium. The laboratory aspects (molecular biology analysis) of the project were supported by the BecA-ILRI Hub through the Africa Biosciences Challenge Fund (ABCF) programme. The ABCF Programme is funded by the Australian Department for Foreign Affairs and Trade (DFAT) through the BecA-CSIRO partnership; the Syngenta Foundation for Sustainable Agriculture (SFSA); the Bill & Melinda Gates Foundation (BMGF); the UK Department for International Development (DFID); and the Swedish International Development Cooperation Agency (Sida). The ABCF Fellowship awarded to GAS was funded by BMGF grant (OPP1075938). Sample collection, field equipment and preliminary sample processing were supported through the “Theileria” project co-funded to the Université Evangélique en Afrique (UEA) by the Agence Universitaire de la Francophonie (AUF) and the Communauté Economique des Pays des Grands Lacs (CEPGL). The International Foundation for Science (IFS, Stockholm, Sweden) supported the individual scholarship awarded to GSA (grant no. IFS-92890CA3) for field work and part of field equipment to the “Theileria” project.http://www.parasitesandvectors.comam2020Veterinary Tropical Disease

Interdisciplinary approach to combat food and nutrition insecurity in rural resource-poor settings of Central Tanzania

Rural resource-poor settings of central depend largely on crop and livestock production for the livelihood. Lack of diversity and adequate food is an important problem affecting a substantial number of communities in Tanzania especially children aged between six months and one year. Poultry and crop production interventions were part of the project titled “strengthening food and nutrition security through family poultry and crop integration in Tanzania and Zambia" that aimed at utilizing locally available resources to mitigate food and nutrition insecurity. Interdisciplinary approach to combat food and nutrition insecurity was conducted in Iwondo Ward located in Mpwapwa District in Dodoma Region, Tanzania. The crop production interventions were introduction of Good Agricultural Practices (GAP) and poultry production interventions were vaccination against Newcastle Disease (ND) based on vaccination calendar and good husbandry. The data in poultry and crop production were collected before introduction of the interventions as the baseline and after introduction of GAP and vaccination of chickens. The harvest of crops was increased as compared to baseline year. The yield of sorghum increased from 200 to 1206.5kg, sesame from 150 to 504kg, and green gram from 80 to 644kg per acre. The proportion of households experiencing hunger for two to three months declined from 58% during baseline to 16% in 2017.The proportion of households keeping chickens increased during the period 2016 to 2018, from 47.3% (n=280) to 82.1% (n=276). The average number of chickens raised by households also increased from 9 to 13, and the average flock structure comprising of chickens of different age categories also demonstrated an increase, adults, 3 to 5, growers, 3 to 4 and chicks, 2 to 4.Most households (89%) reported to provide sorghum, maize/maize bran and finger millet as additional feed to chickens. Adopting interdisciplinary interventions can assist to improve agricultural production and hence increase resilience to food and nutrition insecurity

Molecular epidemiology of Theileria parva in Eastern Zone of Tanzania.

Theileria parva is a haemoprotozoan parasite that causes fatal lymphoproliferative disease of cattle, East Coast fever (ECF), transmitted by Rhipicephalus appendiculatus tick. There are many stocks of T. parva differing in various features. Immunity elicited by immunization is stock specific and therefore, it is appropriate to characterize T. parva to find most relevant stocks for inclusion in the vaccine. This study determined molecular epidemiology of T. parva parasite in Eastern Zone of Tanzania by conventional polymerase chain reaction (PCR) and semi-nested PCR to amplify antigenic genes coding for sporozoite surface protein (p67) and piroplasm proteins (p104) respectively using DNA extracted from cattle blood samples naturally infected with T. parva. Restriction fragments length polymorphism (RFLP) profiles of p104 were generated by Arthrobacter luteus I (Alu I) restriction enzyme. Results demonstrated two types of p67 bands, 750 bp and 950 bp. Profiles for p104 PCR-RFLP revealed 5 types of stocks; the first and the second stocks produced PCR-RFLP profiles identical to T. parva Katete and T. parva Muguga. The p104 PCR-RFLP profiles of the rest three stocks were distinct novel variant stocks never reported in previous studies. The significance of the different p67 alleles and the novel variants stocks detected by p104 PCR-RFLP in the epidemiology of theileriosis in Eastern Zone of Tanzania and the key aspects for vaccine developement is discussed

Population genetic analysis of Theileria parva isolated in cattle and buffaloes in Tanzania using minisatellite and microsatellite markers

A population genetic study of Theileria parva was conducted on 103 cattle and 30 buffalo isolates from Kibaha, Lushoto, Njombe Districts and selected National parks in Tanzania. Bovine blood samples were collected from these study areas and categorized into 5 populations; Buffalo, Cattle which graze close to buffalo, Kibaha, Lushoto and Njombe. Samples were tested by nested PCR for T. parva DNA and positives were compared for genetic diversity to the T. parva Muguga vaccine reference strain, using 3 micro and 11 minisatellite markers selected from all 4 chromosomes of the parasite genome. The diversity across populations was determined by the mean number of different alleles, mean number of effective alleles, mean number of private allele and expected heterozygosity. The mean number of allele unique to populations for Cattle close to buffalo, Muguga, Njombe, Kibaha, Lushoto and Buffalo populations were 0.18, 0.24, 0.63, 0.71, 1.63 and 3.37, respectively. The mean number of different alleles ranged from 6.97 (Buffalo) to 0.07 (Muguga). Mean number of effective alleles ranged from 4.49 (Buffalo) to 0.29 (Muguga). The mean expected heterozygosity were 0.07 0.29, 0.45, 0.48, 0.59 and 0.64 for Muguga, cattle close to buffalo, Kibaha, Njombe, Lushoto and Buffalo populations, respectively. The Buffalo and Lushoto isolates possessed a close degree of diversity in terms of mean number of different alleles, effective alleles, private alleles and expected heterozygosity. The study revealed more diversity in buffalo isolates and further studies are recommended to establish if there is sharing of parasites between cattle and buffaloes which may affect the effectiveness of the control methods currently in use

Participatory epidemiology: Principles, practice, utility, and lessons learnt

Participatory epidemiology (PE) evolved as a branch of veterinary epidemiology and has been largely employed for the control and early warning of infectious diseases within resource-limited settings. It was originally based on combining practitioner communication skills with participatory methods to facilitate the involvement of animal caretakers and owners (embracing their knowledge, experience, and motivations) in the identification and assessment of animal disease problems, including in the design, implementation, monitoring and evaluation of disease control programs, policies, and strategies. With the importance of understanding social perceptions and drivers receiving increasing recognition by epidemiologists, PE tools are being adapted for an increasingly wide range of settings and endeavors. More recently, PE tools have been adapted for use in food and nutrition security programs, One Health activities, wildlife disease surveillance and as part of mixed-methods research across a range of socio-economic settings. This review describes the evolution of PE (in relation to veterinary epidemiology and briefly in relation to public health epidemiology), the underpinning philosophy and principles essential to its effective application and the importance of gender-sensitive approaches and data triangulation, including conventional confirmatory testing. The article also provides illustrative examples highlighting the diversity of approaches and applications of PE, hallmarks of successful PE initiatives and the lessons we can learn when these are missing. Finally, we look forward, describing the particular utility of PE for dealing with emerging infectious diseases, gaining attention of field-level cross-sector officials who can escalate concerns to a higher level and for continuing to raise the voices of those less-heard (such as women, minority groups, and remote communities with limited exposure to formal education) in defining the problems and planning activities that will likely impact directly on their well-being and livelihoods