Diagnosis of cattle diseases endemic to sub-Saharan Africa: evaluating a low cost decision support tool in use by veterinary personnel

Livestock Network Analysis for Rhodesiense Human African Trypanosomiasis Control in Uganda

Background: Infected cattle sourced from districts with established foci for Trypanosoma brucei rhodesiense human African trypanosomiasis (rHAT) migrating to previously unaffected districts, have resulted in a significant expansion of the disease in Uganda. This study explores livestock movement data to describe cattle trade network topology and assess the effects of disease control interventions on the transmission of rHAT infectiousness. Methods: Network analysis was used to generate a cattle trade network with livestock data which was collected from cattle traders (n = 197) and validated using random graph methods. Additionally, the cattle trade network was combined with a susceptible, infected, recovered (SIR) compartmental model to simulate spread of rHAT (R _o 1.287), hence regarded as "slow" pathogen, and evaluate the effects of disease interventions. Results: The cattle trade network exhibited a low clustering coefficient (0.5) with most cattle markets being weakly connected and a few being highly connected. Also, analysis of the cattle movement data revealed a core group comprising of cattle markets from both eastern (rHAT endemic) and northwest regions (rHAT unaffected area). Presence of a core group may result in rHAT spread to unaffected districts and occurrence of super spreader cattle market or markets in case of an outbreak. The key cattle markets that may be targeted for routine rHAT surveillance and control included Namutumba, Soroti, and Molo, all of which were in southeast Uganda. Using effective trypanosomiasis such as integrated cattle injection with trypanocides and spraying can sufficiently slow the spread of rHAT in the network. Conclusion: Cattle trade network analysis indicated a pathway along which T. b. rhodesiense could spread northward from eastern Uganda. Targeted T. b. rhodesiense surveillance and control in eastern Uganda, through enhanced public-private partnerships, would serve to limit its spread.

Genetic Analyses and Genome-Wide Association Studies on Pathogen Resistance of Bos taurus and Bos indicus Cattle Breeds in Cameroon

Autochthonous taurine and later introduced zebu cattle from Cameroon differ considerably in their resistance to endemic pathogens with little to no reports of the underlying genetic make-up. Breed history and habitat variations are reported to contribute significantly to this diversity worldwide, presumably in Cameroon as well, where locations diverge in climate, pasture, and prevalence of infectious agents. In order to investigate the genetic background, the genotypes of 685 individuals of different Cameroonian breeds were analysed by using the BovineSNP50v3 BeadChip. The variance components including heritability were estimated and genome-wide association studies (GWAS) were performed. Phenotypes were obtained by parasitological screening and categorised in Tick-borne pathogens (TBP), gastrointestinal nematodes (GIN), and onchocercosis (ONC). Estimated heritabilities were low for GIN and TBP (0.079 (se = 0.084) and 0.109 (se = 0.103) respectively) and moderate for ONC (0.216 (se = 0.094)). Further than revealing the quantitative nature of the traits, GWAS identified putative trait-associated genomic regions on five chromosomes, including the chromosomes 11 and 18 for GIN, 20 and 24 for TBP, and 12 for ONC. The results imply that breeding for resistant animals in the cattle population from Northern Cameroon might be possible for the studied pathogens; however, further research in this field using larger datasets will be required to improve the resistance towards pathogen infections, propose candidate genes or to infer biological pathways, as well as the genetic structures of African multi-breed populations.

Pharma to farmer: field challenges of optimizing trypanocide use in African animal trypanosomiasis

Trypanocides are a key control component of African animal trypanosomiasis (AAT) in tsetse-infested areas of sub-Saharan Africa. While farmers are dependent upon trypanocides, recent research highlights their inappropriate and ineffective use, problems with drug quality, and treatment failure. There are currently gaps in knowledge and investment in inexpensive AAT diagnostics, understanding of drug resistance, and the effective use of trypanocides in the field. Without this important knowledge it is difficult to develop best practice and policy for existing drugs or to inform development and use of new drugs. There needs to be better understanding of the drivers and behavioural practices around trypanocide use so that they can be incorporated into sustainable solutions needed for the development of effective control of AAT.

Participatory epidemiology of endemic diseases in West African cattle - Ethnoveterinary and bioveterinary knowledge in Fulani disease control

Fulani pastoralists in Nigeria lack adequate access to good quality veterinary services and often resort to treating their animals themselves. There are several negative aspects to this, including poor treatment outcomes, misuse of veterinary drugs and subsequent resistance, and further barriers to good relations between pastoralists and veterinary services. A participatory epidemiology survey was undertaken in Fulani communities, to examine their ability to diagnose and treat bovine diseases. Qualitative participatory epidemiology techniques including semi-structured interviews, ranking and participant and non-participant observations were used for data collection. Quantitative analysis to match Fulani disease descriptions to veterinary diseases was done by hierarchical clustering and multi-dimensional scaling. A concurrent parasitological survey for soil-transmitted parasites, trypanosomiasis and tick-borne diseases was undertaken to validate results. Fulani pastoralists displayed high levels of ethnoveterinary knowledge and good clinical diagnostic abilities. Diseases considered important by pastoralists included: hanta (CBPP); sammore (trypanosomiasis); boro (foot and mouth disease), gortowel (liver fluke), dauda (parasitic gastro-enteritis with bloody diarrhoea) and susa (parasitic gastro-enteritis). The parasitology survey supported the participatory epidemiology results but also showed a high prevalence of tick-borne diseases that were not mentioned by pastoralists in this study. The use of "hanta" to describe CBPP is important as the accepted translation is liver-fluke (hanta is the Hausa word for liver). Gortowel and dauda, two previously undescribed Fulfulde disease names have now been matched to liver fluke and PGE with bloody diarrhoea. Fulani showed low levels of bovine veterinary knowledge with mostly incorrect veterinary drugs chosen for treatment. Levels of ethno- and bio-veterinary knowledge and their application within pastoralist livestock healthcare practices are discussed.

Assisting differential clinical diagnosis of cattle diseases using smartphone-based technology in low resource settings: a pilot study

Background

The recent rise in mobile phone use and increased signal coverage has created opportunities for growth of the mobile Health sector in many low resource settings. This pilot study explores the use of a smartphone-based application, VetAfrica-Ethiopia, in assisting diagnosis of cattle diseases. We used a modified Delphi protocol to select important diseases and Bayesian algorithms to estimate the related disease probabilities based on various clinical signs being present in Ethiopian cattle.

Results

A total of 928 cases were diagnosed during the study period across three regions of Ethiopia, around 70% of which were covered by diseases included in VetAfrica-Ethiopia. Parasitic Gastroenteritis (26%), Blackleg (8.5%), Fasciolosis (8.4%), Pasteurellosis (7.4%), Colibacillosis (6.4%), Lumpy skin disease (5.5%) and CBPP (5.0%) were the most commonly occurring diseases. The highest (84%) and lowest (30%) levels of matching between diagnoses made by student practitioners and VetAfrica-Ethiopia were for Babesiosis and Pasteurellosis, respectively. Multiple-variable logistic regression analysis indicated that the putative disease indicated, the practitioner involved, and the level of confidence associated with the prediction made by VetAfrica-Ethiopia were major determinants of the likelihood that a diagnostic match would be obtained.

Conclusions

This pilot study demonstrated that the use of such applications can be a valuable means of assisting less experienced animal health professionals in carrying out disease diagnosis which may lead to increased animal productivity through appropriate treatment.

Proof of concept of faecal egg nematode counting as a practical means of veterinary engagement with planned livestock health management in a lower income country

BACKGROUND

The wellbeing and livelihood of farmers in impoverished regions of the world is intrinsically linked to the health and welfare of their livestock; hence improved animal health is a pragmatic component of poverty alleviation. Prerequisite knowledge and understanding of the animal health challenges facing cattle keepers in Malawi is constrained by the lack of veterinary infrastructure, which inevitably accompanies under-resourced rural development in a poor country.

METHODS

We collaborated with public and private paraveterinary services to locate 62 village Zebu calves and 60 dairy co-operative calves dispersed over a wide geographical area. All calves were visited twice about 2 to 3 weeks apart, when they were clinically examined and faecal samples were collected. The calves were treated with 7.5 mg/kg of a locally-available albendazole drench on the first visit, and pre- and post- treatment trichostrongyle and Toxocara faecal egg counts were performed using a modified McMaster method.

RESULTS

Our clinical findings point towards a generally poor level of animal health, implying a role of ticks and tick-transmitted diseases in village calves and need for improvement in neonatal calf husbandry in the dairy co-operative holdings. High faecal trichostrongyle egg counts were not intuitive, based on our interpretation of the animal management information that was provided. This shows the need for better understanding of nematode parasite epidemiology within the context of local husbandry and environmental conditions. The albendazole anthelmintic was effective against Toxocara, while efficacy against trichostrongyle nematodes was poor in both village and dairy co-operative calves, demonstrating the need for further research to inform sustainable drug use.

CONCLUSIONS

Here we describe the potential value of faecal nematode egg counting as a platform for communicating with and gaining access to cattle keepers and their animals, respectively, in southern Malawi, with the aim of providing informative background knowledge and understanding that may aid in the establishment of effective veterinary services in an under-resourced community.

Infections and risk factors for livestock with species of Anaplasma, Babesia and Brucella under semi-nomadic rearing in Karamoja Region, Uganda

A survey was conducted to estimate the prevalence of Anaplasma, Babesia and Brucella spp. infections in cattle, goats and sheep in the Karamoja Region of Uganda and to identify possible risk factors existing in this semi-nomadic and pastoral area. Low cost laboratory tests were used to diagnose infections (Rose Bengal test for Brucella spp. antibodies and direct microscopic examination for Anaplasma and Babesia spp.). Multivariable logistic regression models were applied to identify possible risk factors linked to gender, animal species, age (only for cattle) and districts. A total of 3935 cattle, 729 goats and 306 sheep of five districts of the Karamoja Region were tested. Seroprevalence for Brucella was 9.2 % (CI, 95 %: 8.4-10), for Anaplasma 19.5 % (CI 95 %: 18.4-20.6) and for Babesia 16 % (CI 95 %: 15-17.1). Significant differences in infections prevalence were observed against risk factors associated with districts and species. Cattle were the species with higher risk of the infections. Female gender was identified as at risk only for Brucella spp. infection. Cattle more than one year old had greater likelihood to be Brucella seropositive. Co-infections of Anaplasma and Babesia spp. were statistically associated, especially in goats and sheep. Further studies to identify risk factors related to host species and geographical districts are needed. The influence on the semi-nomadic agro-pastoral system in Karamoja of animal raids and animal mixing should be further investigated. Findings were important to sensitize Karamojong undertaking measures on infection control, especially on cattle, which are their main source of food.

Infections and risk factors for livestock with species of Anaplasma, Babesia and Brucella under semi-nomadic rearing in Karamoja Region, Uganda

A survey was conducted to estimate the prevalence of Anaplasma, Babesia and Brucella spp. infections in cattle, goats and sheep in the Karamoja Region of Uganda and to identify possible risk factors existing in this semi-nomadic and pastoral area. Low cost laboratory tests were used to diagnose infections (Rose Bengal test for Brucella spp. antibodies and direct microscopic examination for Anaplasma and Babesia spp.). Multivariable logistic regression models were applied to identify possible risk factors linked to gender, animal species, age (only for cattle) and districts. A total of 3935 cattle, 729 goats and 306 sheep of five districts of the Karamoja Region were tested. Seroprevalence for Brucella was 9.2 % (CI, 95 %: 8.4-10), for Anaplasma 19.5 % (CI 95 %: 18.4-20.6) and for Babesia 16 % (CI 95 %: 15-17.1). Significant differences in infections prevalence were observed against risk factors associated with districts and species. Cattle were the species with higher risk of the infections. Female gender was identified as at risk only for Brucella spp. infection. Cattle more than one year old had greater likelihood to be Brucella seropositive. Co-infections of Anaplasma and Babesia spp. were statistically associated, especially in goats and sheep. Further studies to identify risk factors related to host species and geographical districts are needed. The influence on the semi-nomadic agro-pastoral system in Karamoja of animal raids and animal mixing should be further investigated. Findings were important to sensitize Karamojong undertaking measures on infection control, especially on cattle, which are their main source of food.

Contribution of draft cattle to rural livelihoods in a district of southeastern Uganda endemic for bovine parasitic diseases: an economic evaluation

Background

A study was conducted in Tororo District in eastern Uganda to assess the socio-economic contribution of draft cattle to rural livelihoods. The aim of the study was to empirically quantify the economic value of draft cattle thus contributing to understanding the impact of endemic parasitic diseases of cattle on livestock productivity and subsequently household income, labor and food security.

Method

A total of 205 draft cattle keeping households (n = 205) were randomly selected and structured household questionnaires were administered, focusing on work oxen use, productivity, inputs and outputs. The data obtained was analyzed using standard statistical methods and used to calculate the gross margin from the draft cattle enterprise. Secondary data were obtained from focus group discussions and key informant interviews and these were analyzed using Bayesian methods.

Results

The study showed that, apart from being labor saving, the use of animal traction is highly profitable with the gross margin per year from the use of draft cattle amounting to 245 United States dollars per work oxen owning household. The cash obtained from hiring out draft animals was equivalent to nearly a quarter of the average local household’s monetary receipts. It also revealed that endemic bovine parasitic diseases such as trypanosomiasis and tick-borne diseases reduced draft cattle output by 20.9 % and potential household income from the use of draft oxen by 32.2 %.

Conclusion

The presence of endemic cattle diseases in rural Uganda is adversely affecting the productivity of draft cattle, which in turn affects household income, labor and ultimately food security. This study highlights the contribution of draft cattle to rural livelihoods, thus increasing the expected impact of cost-effective control strategies of endemic production limiting livestock diseases in Uganda.

Mixed methods evaluation of targeted selective anthelmintic treatment by resource-poor smallholder goat farmers in Botswana

Due to the threat of anthelmintic resistance, livestock farmers worldwide are encouraged to selectively apply treatments against gastrointestinal nematodes (GINs). Targeted selective treatment (TST) of individual animals would be especially useful for smallholder farmers in low-income economies, where cost-effective and sustainable intervention strategies will improve livestock productivity and food security. Supporting research has focused mainly on refining technical indicators for treatment, and much less on factors influencing uptake and effectiveness. We used a mixed method approach, whereby qualitative and quantitative approaches are combined, to develop, implement and validate a TST system for GINs in small ruminants, most commonly goats, among smallholder farmers in the Makgadikgadi Pans region of Botswana, and to seek better understanding of system performance within a cultural context. After the first six months of the study, 42 out of 47 enrolled farmers were followed up; 52% had monitored their animals using the taught inspection criteria and 26% applied TST during this phase. Uptake level showed little correlation with farmer characteristics, such as literacy and size of farm. Herd health significantly improved in those herds where anthelmintic treatment was applied: anaemia, as assessed using the five-point FAMACHA(©) scale, was 0.44-0.69 points better (95% confidence interval) and body condition score was 0.18-0.36 points better (95% C.I., five-point scale) in treated compared with untreated herds. Only targeting individuals in greatest need led to similar health improvements compared to treating the entire herd, leading to dose savings ranging from 36% to 97%. This study demonstrates that TST against nematodes can be implemented effectively by resource-poor farmers using a community-led approach. The use of mixed methods provides a promising system to integrate technical and social aspects of TST programmes for maximum uptake and effect.

FAMACHA©: A potential tool for targeted selective treatment of chronic fasciolosis in sheep

The liver fluke Fasciola hepatica causes considerable damage to the health, welfare and productivity of ruminants in temperate areas, and its control is challenged by anthelmintic resistance. Targeted selective treatment (TST) is an increasingly established strategy for preserving anthelmintic efficacy in grazing livestock, yet no practical indicators are available to target individuals for treatment against fluke infection. This paper evaluates the FAMACHA(©) system, a colour chart for the non-invasive detection of anaemia in small ruminants, for this purpose. FAMACHA(©) scores were collected from 288 sheep prior to slaughter during the winter period, when fluke infections were largely mature, and condemned livers were recovered and adult flukes extracted. Average FAMACHA(©) score was significantly higher (=paler conjunctivae) in animals whose livers were condemned (3.6, n=62) than in those whose livers were not condemned (2.1). The number of adult flukes recovered ranged from 2 to 485, and was positively correlated with FAMACHA(©) score (r(2)=0.54, p<0.001). Packed cell volume was correlated negatively with both FAMACHA(©) score (n=240, r=0.23, p<0.001) and fluke number (r=0.24, p<0.001). Nematode faecal egg count (FEC) did not correlate with FAMACHA(©) score, and selective treatment of individual sheep with FAMACHA(©) scores above 2 or 3 would have preserved between 27 and 100% of nematodes in refugia on the basis of FEC, depending on group and the threshold used for treatment. FAMACHA(©) holds promise as a tool for selective treatment of sheep against adult F. hepatica, in support of refugia-based control of fluke and nematode infections, and further field evaluation is warranted.