A farmer-friendly tool for estimation of weights of pigs kept by smallholder farmers in Uganda.

Pig keeping is important to the livelihoods of many rural Ugandans. Pigs are typically sold based on live weight or a carcass weight derived from this; however this weight is commonly estimated due to the lack of access to scales. Here, we explore the development of a weigh band for more accurate weight determination and potentially increased farmer bargaining power on sale price. Pig weights and varied body measurements (heart girth, height, and length) were collected on 764 pigs of different ages, sex, and breed types, from 157 smallholder pig keeping households in Central and Western Uganda. Mixed-effects linear regression analyses, with household as a random effect and the varied body measurements as a fixed effect, were performed to determine the best single predictor for cube root of weight (transformation of weight for normality), for 749 pigs ranging between 0 and 125 kg. The most predictive single body measurement was heart girth, where weight in kg = (0.4011 + heart girth in cm × 0.0381)3. This model was found to be most suitable for pigs between 5 and 110 kg, notably more accurate than farmers' estimates, but still with somewhat broad confidence intervals (for example, ±11.5 kg for pigs with a predicted weight of 51.3 kg). We intend to pilot test a weigh band based on this model before deciding on whether it is suitable for wider scaling.

Morphological characterization and immunohistochemical detection of the proinflammatory cytokines IL-1ß, IL-17A, and TNF-α in lung lesions associated with contagious bovine pleuropneumonia.

Contagious bovine pleuropneumonia (CBPP), a severe respiratory disease, is characterized by massive inflammation of the lung especially during the acute clinical stage of infection. Tissue samples from cattle, experimentally infected with Mycoplasma mycoides subsp. mycoides Afadé, were subjected to histopathological and immunohistochemical examination in order to provide insight into innate immune pathways that shape inflammatory host responses. Lung lesions were characterized by vasculitis, necrosis, and increased presence of macrophages and neutrophils, relative to uninfected animals. The presence of three cytokines associated with innate inflammatory immune responses, namely, IL-1ß, IL-17A, and TNF-α, were qualitatively investigated in situ. Higher cytokine levels were detected in lung tissue samples from CBPP-affected cattle compared to samples derived from an uninfected control group. We therefore conclude that the cytokines TNF-α and IL-1ß, which are prevalent in the acute phase of infections, play a role in the inflammatory response seen in the lung tissue in CBPP. IL-17A gets released by activated macrophages and attracts granulocytes that modulate the acute phase of the CBPP lesions.

Current and potential use of animal disease data by stakeholders in the global south and north.

What cannot be measured will not be managed. The Global Burden of Animal Diseases (GBADs) will generate information on animal disease burdens by species, production system, type and gender of farmer and consumer, geographical region, and time period. To understand the demand for burden of animal disease (BAD) data and how end-users might benefit from this, we reviewed the literature on animal diseases prioritisation processes (ADPP) and conducted a survey of BAD information users. The survey covered their current use of data and prioritizations as well as their needs for different, more, and better information. We identified representative (geography, sector, species) BAD experts from the authors' networks and publicly available documents and e-mailed 1485 experts. Of 791 experts successfully contacted, 271 responded (34% response rate), and 185 complete and valid responses were obtained. Most respondents came from the public sector followed by academia/research, and most were affiliated to institutions in low- and middle-income countries (LMICs). Of the six ADPPs commonly featured in literature, only three were recognised by more than 40% of experts. An additional 23 ADPPs were used. Awareness of ADDPs varied significantly by respondents. Respondents ranked animal disease priorities. We used exploded logit to combine first, second and third disease priorities to better understand prioritzation and their determinants. Expert priorities differed significantly from priorities identified by the ADDPs, and also from the priorities stated veterinary services as reported in a survey for a World Organisation of Animal Health (WOAH) technical item. Respondents identified 15 different uses of BAD data. The most common use was presenting evidence (publications, official reports, followed by disease management, policy development and proposal writing). Few used disease data for prioritzation or resource allocation, fewer routinely used economic data for decision making, and less than half were aware of the use of decision support tools (DSTs). Nearly all respondents considered current BAD metrics inadequate, most considered animal health information insufficiently available and not evidence-based, and most expressed concerns that decision-making processes related to animal health lacked transparency and fairness. Cluster analysis suggested three clusters of BAD users and will inform DSTs to help them better meet their specific objectives. We conclude that there is a lack of satisfaction with current BAD information, and with existing ADDPs, contributing to sub-optimal decision making. Improved BAD data would have multiple uses by different stakeholders leading to better evidenced decisions and policies; moreover, clients will need support (including DSTs) to optimally use BAD information.

Mortality in East African shorthorn zebu cattle under one year: predictors of infectious-disease mortality.

BACKGROUND: Infectious livestock diseases remain a major threat to attaining food security and are a source of economic and livelihood losses for people dependent on livestock for their livelihood. Knowledge of the vital infectious diseases that account for the majority of deaths is crucial in determining disease control strategies and in the allocation of limited funds available for disease control. Here we have estimated the mortality rates in zebu cattle raised in a smallholder mixed farming system during their first year of life, identified the periods of increased risk of death and the risk factors for calf mortality, and through analysis of post-mortem data, determined the aetiologies of calf mortality in this population. A longitudinal cohort study of 548 zebu cattle was conducted between 2007 and 2010. Each calf was followed during its first year of life or until lost from the study. Calves were randomly selected from 20 sub-locations and recruited within a week of birth from different farms over a 45 km radius area centered on Busia in the Western part of Kenya. The data comprised of 481.1 calf years of observation. Clinical examinations, sample collection and analysis were carried out at 5 week intervals, from birth until one year old. Cox proportional hazard models with frailty terms were used for the statistical analysis of risk factors. A standardized post-mortem examination was conducted on all animals that died during the study and appropriate samples collected. RESULTS: The all-cause mortality rate was estimated at 16.1 (13.0-19.2; 95% CI) per 100 calf years at risk. The Cox models identified high infection intensity with Theileria spp., the most lethal of which causes East Coast Fever disease, infection with Trypanosome spp., and helminth infections as measured by Strongyle spp. eggs per gram of faeces as the three important infections statistically associated with infectious disease mortality in these calves. Analysis of post-mortem data identified East Coast Fever as the main cause of death accounting for 40% of all deaths, haemonchosis 12% and heartwater disease 7%. CONCLUSION: The findings demonstrate the impact of endemic parasitic diseases in indigenous animals expected to be well adapted against disease pressures. Additionally, agreement between results of Cox models using data from simple diagnostic procedures and results from post-mortem analysis underline the potential use such diagnostic data to reduce calf mortality. The control strategies for the identified infectious diseases have been discussed.

Traditional breeding objectives and practices of goat, sheep and cattle smallholders in The Gambia and implications in relation to the design of breeding interventions.

This paper describes the traditional breeding objectives and practices of West African Dwarf goat, Djallonke sheep, and N'dama cattle keepers in The Gambia and discusses the implications of these on the design of breeding-related interventions to improve livestock productivity. Data were collected via surveys implemented within three study sites in The Gambia, where traditional mixed crop-livestock smallholder farming predominates. The surveys comprised a participatory rural appraisal conducted in nine communities and a household questionnaire targeting 238 households. Livestock-keeping households were classified as 'poorer' or 'wealthier' based on the number of cattle owned. The most important objectives for keeping all species of livestock for the poorer groups (0 to 10 cattle) was 'savings and insurance', followed by 'income' and 'ceremonial/dowry' for the small ruminants and 'manure' and 'draught' for both cows and bulls. In contrast, for the wealthier group (more than 10 cattle), savings and insurance was the fourth to seventh ranked production objective (depending on species), with the most important production objectives being ceremonial/dowry for goats, income for sheep and manure for cows and bulls. An analysis of breeding practices indicated that breeding animals are selected on criteria which partially align to the breeding objectives, animals are rarely purchased for the purpose of breed improvement, knowledge of the cause and consequence of inbreeding is low and breeding decision makers may not necessarily be the livestock owner, particularly if the livestock owner is a women. Given this, it is suggested that capacity building on breeding-related issues, particularly in relation to the selection of breeding animals and specifically targeted at the different socioeconomic groups of livestock keepers, may be an appropriate, effective and relatively low-cost breeding intervention.

Plasma levels of TNF-α, IFN-γ, IL-4 and IL-10 during a course of experimental contagious bovine pleuropneumonia.

BACKGROUND: Contagious Bovine Pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides, is widespread in sub-Saharan Africa. The current live vaccine T1/44 has limited efficacy and occasionally leads to severe side effects in the animals. A better understanding of the immune responses triggered by Mycoplasma mycoides subsp. mycoides and their role in disease progression will help to facilitate the design of a rational vaccine. Currently, knowledge of cytokines involved in immunity and immunopathology in CBPP is rather limited. The aim of this study was to characterize the in vivo plasma concentrations of the cytokines TNF-α, IFN-γ, IL-4, IL-10 and the overall role of CD4+ T cells in the development of cytokine levels during a primary infection. Plasma cytokine concentrations in two groups of cattle (CD4+ T cell-depleted and non-depleted cattle) experimentally infected with Mycoplasma mycoides subsp. mycoides were measured and their relationship to the clinical outcomes was investigated. RESULTS: Plasma cytokine concentrations varied between animals in each group. Depletion of CD4+ T cells did not induce significant changes in plasma levels of TNF-α, IL-4, and IL-10, suggesting a minor role of CD4+ T cells in regulation or production of the three cytokines during the time window of depletion (1-2 weeks post depletion). Unexpectedly, the IFN-γ concentrations were slightly, but statistically significantly higher in the depleted group (p < 0.05) between week three and four post infection. Three CD4+ T cell-depleted animals that experienced severe disease, had high levels of TNF-α and IFN-γ. Only one severely diseased non-depleted animal showed a high serum concentration of IL-4 post infection. CONCLUSIONS: Comparison of most severely diseased animals, which had to be euthanized prior to the expected date, versus less severe diseased animals, irrespective of the depletion status, suggested that high TNF-α levels are correlated with more severe pathology in concomitance with high IFN-γ levels.

Impact of participatory training of smallholder pig farmers on knowledge, attitudes and practices regarding biosecurity for the control of African swine fever in Uganda.

We evaluated the impact of a participatory training of pig farmers on knowledge, attitude and practices (KAP) of biosecurity relating to ASF control in two districts of Uganda using a randomized control trial (RCT). A total of 830 pig farmers from 32 villages were included in the study, with 425 farmers receiving training, while 405 did not. An item response theory model was used to assess the impact of the training on farmer's KAP. Logistic regression models were used to assess the factors that affected knowledge gain and change in attitude and practices after training. Focus group discussions (FGD) were carried out with selected farmers from the treatment group at the end of the intervention, to share their experiences and discuss potential factors that could hinder adoption of biosecurity in their communities. Results of the regression analyses showed that there was a significant effect of biosecurity training (p = .038) on gain in knowledge after 12 months, but there were limited changes in farmer's attitude and practice at 12 and 28 months after training. Pig production domain (peri-urban/urban production), group membership, gender (male) and education of the farmer positively influenced knowledge gain and attitude of farmers towards biosecurity. This paper provides empirical evidence on the impact of training intervention on biosecurity practices for disease prevention or control. In addition, it breaks down the components of the biosecurity practices and documents the specific challenges to its uptake by the farmers. It therefore relaxes the assumption of knowledge constraint as a barrier to uptake. The results clearly show that knowledge is not the binding constraint to uptake of the biosecurity interventions.

Assessment of in vitro interferon-gamma responses from peripheral blood mononuclear cells of cattle infected with Mycoplasma mycoides ssp. mycoides small colony type.

Contagious bovine pleuropneumonia (CBPP) is a lung disease caused by the bacterial pathogen Mycoplasma mycoides ssp. mycoides small colony type (MmmSC). It has been spreading due to a number of factors including poor vaccine efficacy and poor sensitivity of current diagnostic tests. The purpose of this study was to assess interferon gamma (IFN-gamma) release after stimulation of peripheral blood mononuclear cells (PBMC) from experimentally infected cattle. PBMC collected from 15 artificially infected animals were incubated with different concentrations of total MmmSC antigen. After 72h of incubation the IFN-gamma release was measured and found to be elevated in 11 animals. We did not observe a correlation between IFN-gamma release of animals with and without pathomorphological gross lesions. Therefore, our data do not confirm a role for CD4 T-lymphocytes in protection, since there is no correlation between IFN-g secretion (supposed to be mainly derived from CD4 T-cells) and disease severity. Additionally, we applied immunocytochemistry on affected lung tissue and detected no build up of T-lymphocytes (CD4 T-cells, CD8 T-cells) but a high presence of myeloid cells.

An Ad/MVA vectored Theileria parva antigen induces schizont-specific CD8+ central memory T cells and confers partial protection against a lethal challenge.

The parasite Theileria parva is the causative agent of East Coast fever (ECF), one of the most serious cattle diseases in sub-Saharan Africa, and directly impacts smallholder farmers' livelihoods. There is an efficient live-parasite vaccine, but issues with transmission of vaccine strains, need of a cold chain, and antibiotics limit its utilization. This has fostered research towards subunit vaccination. Cytotoxic T lymphocytes (CTL) are crucial in combating the infection by lysing T. parva-infected cells. Tp1 is an immunodominant CTL antigen, which induces Tp1-specific responses in 70-80% of cattle of the A18 or A18v haplotype during vaccination with the live vaccine. In this study, human adenovirus serotype 5 (HAd5) and modified vaccinia Ankara (MVA) were assessed for their ability to induce Tp1-specific immunity. Both viral vectors expressing the Tp1 antigen were inoculated in cattle by a heterologous prime-boost vaccination regimen. All 15 animals responded to Tp1 as determined by ELISpot. Of these, 14 reacted to the known Tp1 epitope, assayed by ELISpot and tetramer analyses, with CTL peaking 1-week post-MVA boost. Eleven animals developed CTL with specific cytotoxic activity towards peripheral blood mononuclear cells (PBMC) pulsed with the Tp1 epitope. Moreover, 36% of the animals with a Tp1 epitope-specific response survived a lethal challenge with T. parva 5 weeks post-MVA boost. Reduction of the parasitemia correlated with increased percentages of central memory lymphocytes in the Tp1 epitope-specific CD8+ populations. These results indicate that Tp1 is a promising antigen to include in a subunit vaccine and central memory cells are crucial for clearing the parasite.

Immune parameters to p67C antigen adjuvanted with ISA206VG correlate with protection against East Coast fever.

East Coast fever (ECF) is a lymphoproliferative disease caused by the tick-transmitted protozoan parasite Theileria parva. ECF is one of the most serious cattle tick-borne diseases in Sub-Saharan Africa. We have previously demonstrated that three doses of the C-terminal part of the sporozoite protein p67 (p67C) adjuvanted with ISA206VG confers partial protection against ECF at a herd level. We have tested the efficacy of two doses of this experimental vaccine, as reducing the vaccination regimen would facilitate its deployment in the field. We reconfirm that three antigen doses gave a significant level of protection to severe disease (46%, ECF score < 6) when compared with the control group, while two doses did not (23%). Animals receiving three doses of p67C developed higher antibody titers and CD4+ T-cell proliferation indices, than those which received two doses. A new panel of immune parameters were tested in order to identify factors correlating with protection: CD4+ proliferation index, total IgG, IgG1, IgG2 and IgM half maximal titers and neutralization capacity of the sera with and without complement. We show that some of the cellular and humoral immune responses provide preliminary correlates of protection.

Adherence to secondary prophylaxis for rheumatic heart disease is underestimated by register data.

OBJECTIVE: In high-burden Australian states and territories, registers of patients with acute rheumatic fever and rheumatic heart disease are maintained for patient management, monitoring of system performance and research. Data validation was undertaken for the Australian Northern Territory Rheumatic Heart Disease Register to determine quality and impact of data cleaning on reporting against key performance indicators: overall adherence, and proportion of patients receiving ≥80% of scheduled penicillin doses for secondary prophylaxis. METHODS: Register data were compared with data from health centres. Inconsistencies were identified and corrected; adherence was calculated before and after cleaning. RESULTS: 2780 penicillin doses were validated; 426 inconsistencies were identified, including 102 incorrect dose dates. After cleaning, mean adherence increased (63.5% to 67.3%, p<0.001) and proportion of patients receiving ≥80% of doses increased (34.2% to 42.1%, p = 0.06). CONCLUSIONS: The Northern Territory Rheumatic Heart Disease Register underestimates adherence, although the key performance indicator of ≥80% adherence was not significantly affected. Program performance is better than hitherto appreciated. However some errors could affect patient management, as well as accuracy of longitudinal or inter-jurisdictional comparisons. Adequate resources are needed for maintenance of data quality in acute rheumatic fever/rheumatic heart disease registers to ensure provision of evidence-based care and accurate assessment of program impact.

High antibody titres against predicted Mycoplasma surface proteins do not prevent sequestration in infected lung tissue in the course of experimental contagious bovine pleuropneumonia.

Contagious bovine pleuropneumonia (CBPP), a severe respiratory disease of cattle caused by Mycoplasma mycoides subsp. mycoides (Mmm) is endemic in many African countries due to fragmented veterinary services and the lack of an efficient vaccine and sensitive diagnostics. More efficient tools to control the disease are needed, but to develop the tools, a better understanding of host-pathogen interactions is necessary. The aim of this study was to characterize the kinetics of the humoral immune response against 65 Mmm surface antigens for an extended period in cattle that survived a primary infection with Mmm. We describe clinical and haematological outcomes, and dissect the humoral immune response over time, to specific antigens and compared the antibody responses between different pathomorphological outcomes. No antigen-specific antibodies correlating with protection were identified. Interestingly we found that animals that developed Mycoplasma-containing sequestra had significantly higher antibody levels against proteins comprising the surface proteome than the animals that cleared Mycoplasma from their lungs. Based on these data we suggest that high antibody titres might play a role in the establishment of pathomorphological changes, such as vasculitis, which should be investigated in future studies. Beneficial antibody specificities and cellular immune responses need to be identified in order to foster the development of an improved vaccine in the future.