Goats In Africa Research Articles

Review of the Current Status on Ruminant Abortigenic Pathogen Surveillance in Africa and Asia.

Ruminant abortion events cause economic losses. Despite the importance of livestock production for food security and the livelihoods of millions of people in the world's poorest communities, very little is known about the scale, magnitude, or causes of these abortions in Africa and Asia. The aim of this review was to determine the current status of surveillance measures adopted for ruminant abortigenic pathogens in Africa and Asia and to explore feasible surveillance technologies. A systematic literature search was conducted using PRISMA guidelines for studies published between 1 January 1990 and 1 May 2024 that reported epidemiological surveys of abortigenic pathogens Africa and Asia. A meta-analysis was used to estimate the species-specific sero-prevalence of the abortigenic agents and the regions where they were detected. In the systematic literature search, 39 full-text manuscripts were included. The most prevalent abortigenic pathogens with sero-prevalence greater than 10% were BHV-1, Brucella, Chlamydia abortus, Neospora caninum, RVFV, and Waddlia chondrophila in cattle, BVDV in sheep, and RVFV and Toxoplasma gondii in goats in Africa. In Asia, Anaplasma, BHV-1, Bluetongue virus, Brucella, and BVDV were prevalent in cattle, whereas Mycoplasma was important in goats and sheep.

Molecular prevalence and distribution of tick-borne bacterial and protozoan pathogens of sheep and goats in Africa: A systematic review and meta-analysis

Tick-borne pathogens (TBPs) are a major impediment to the health, welfare, and production of small ruminants across the world, including Africa. Comprehensive information about the epidemiology of TBPs infecting sheep and goats across Africa is lacking. Therefore, this study was undertaken to determine the prevalence through a meta-analysis of selected TBPs in blood DNA from domestic sheep and goats in Africa obtained using molecular-based methods. The literature review was done according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines using five English electronic databases (PubMed, Science Direct, Springer Link, Web of Science, and African Journals Online (AJOL). The search was performed with no restriction in time through to 18th January 2023. Of the 63 full-text articles subjected to eligibility, only 30 articles met the eligibility criteria and were included in the review. The overall pooled prevalence of selected TBPs varied considerably between host species (sheep vs. goats), with Anaplasma ovis (44.50 vs. 48.40%), Ehrlichia ruminantium (5.50 vs. 2.00%), Coxiella burnetii (4.40 vs. 1.70%), Borrelia theileri in sheep (5.20%), Babesia ovis (1.70% vs. 1.90%), Theileria ovis (40.50% vs 10.00%), T. separata (1.00% vs 1.00%) and T. lestoquardi in sheep (8.40%). However, the prevalence of the selected TBPs was generally higher in sheep compared to goats. Several genetic loci were targeted in the characterization of tick-borne pathogens, such as 16S rDNA, groEL, and msp4 for Anaplasma ovis, pCS20 for Ehrlichia ruminantium, Insertion Sequence (IS1111) for Coxiella burnetii, flaB (flagellin) and 16S rRNA for Borrelia theileri, 5.8S rRNA and 18S rRNA for Babesia/Theileria, as well as the utilization of numerous PCR variants including conventional polymerase chain reaction (PCR), nested-PCR, qPCR, Loop-mediated isothermal amplification (LAMP), and reverse line blotting (RLB). In conclusion, A. ovis was the most widely distributed and prevalent TBP affecting small ruminants within the continent. Hence, this warrants adequate attention towards early diagnosis and treatment of infected animals as well as the control of the tick vectors involved in their transmission.

Low-cost molecular methods to characterise gastrointestinal nematode co-infections of goats in Africa

BackgroundVeterinary diagnostics aid intervention strategies, track zoonoses, and direct selective breeding programs in livestock. In ruminants, gastrointestinal nematode (GIN) parasites are a major cause of production losses, but morphologically similar species limit our understanding of how specific GIN co-infections impact health in resource-limited settings. To estimate the presence and relative abundance of GINs and other helminths at the species level, we sought to develop a low-cost and low-resource molecular toolkit applied to goats from rural Malawi smallholdings.MethodsGoats were subjected to health scoring and faecal sampling on smallholdings in Lilongwe district, Malawi. Infection intensities were estimated by faecal nematode egg counts with a faecal subsample desiccated for DNA analysis. Two DNA extraction methods were tested (low-resource magbead kit vs high-resource spin-column kit), with resulting DNA screened by endpoint polymerase chain reaction (PCR), semi-quantitative PCR, quantitative PCR (qPCR), high-resolution melt curve analysis (HRMC), and ‘nemabiome’ internal transcribed spacer 2 (ITS-2) amplicon sequencing.ResultsBoth DNA isolation methods yielded comparable results despite poorer DNA purity and faecal contaminant carryover from the low-resource magbead method. GINs were detected in 100% of samples regardless of infection intensity. Co-infections with GINs and coccidia (Eimeria spp.) were present in most goats, with GIN populations dominated by Haemonchus contortus, Trichostrongylus colubriformis, Trichostrongylus axei, and Oesophagostomum columbianum. Both multiplex PCR and qPCR were highly predictive of GIN species proportions obtained using nemabiome amplicon sequencing; however, HRMC was less reliable than PCR in predicting the presence of particular species.ConclusionsThese data represent the first ‘nemabiome’ sequencing of GINs from naturally infected smallholder goats in Africa and show the variable nature of GIN co-infections between individual animals. A similar level of granularity was detected by semi-quantitative PCR methods, which provided an accurate summary of species composition.Assessing GIN co-infections is therefore possible using cost-efficient low-resource DNA extraction and PCR approaches that can increase the capacity of molecular resources in areas where sequencing platforms are not available; and also open the door to affordable molecular GIN diagnostics. Given the diverse nature of infections in livestock and wildlife, these approaches have potential for disease surveillance in other areas.Graphical

The Prevalence and Determinants of Taenia multiceps Infection (Cerebral Coenurosis) in Small Ruminants in Africa: A Systematic Review

Cerebral coenurosis is a fatal parasitic neurological disease affecting the brain and spinal cord of goats and sheep. Despite the large population of sheep and goats in Africa, there is very little awareness about the scale or effects of the disease. A systematic review was conducted to bridge the gap in the current understanding of the epidemiology of Taenia multiceps coenurosis in Africa. A detailed literature search was conducted in EBSCOhost, Google Scholar, Research4life (AGORA), and PubMed for studies in T. multiceps coenurosis in goats and sheep in Africa for the period spanning January 2000 to December 2019. The search identified 574 publications, of which only 11 studies were eligible, highlighting major gaps in reporting of this disease in Africa. Data were extracted and evidence synthesized in relation to prevalence and determinants for T. multiceps coenurosis. The descriptive summary statistics revealed a median (IQR) prevalence of coenurosis of 22.3% (range: 18.3–26.4 percent) for community based and 14.8% (range: 3.8–45.6) for abattoir-based studies. This high prevalence indicates that Taenia multiceps coenurosis is an important disease for small ruminant productivity in Africa. Knowledge of the determinants of prevalence could be used to inform preventive measures, including behaviour change among livestock keepers and those involved in livestock slaughter to break cycles of transmission between small ruminants and dogs.

EFFECTS OF FEEDING Lantana camara LEAF HAY ON ANIMAL PERFORMANCE AND HEALTH IN SMALL EAST AFRICA GOAT BREEDS

<p><strong>Background:</strong> <em>Lantana camara</em> is listed as one of the worst invasive species worldwide and is considered poisonous to livestock. However, in invaded Zimbabwean rangelands, voluntary intake by domestic livestock especially goats of this shrub is common, yet, little is understood about the effect of this browse on animal performance. <strong>Objectives:</strong> To assess the effects of feeding graded levels of <em>L. camara</em> (LC) leafy hay on the performance, digestibility, nitrogen balance and microbial protein synthesis in Small East Africa Goat Breeds. <strong>Methodology:</strong> Eighteen, six to ten months old castrated goats with a mean± (SD) weight of 13.6±4.9 kg were randomly assigned to the six treatment diets in a completely randomised design. Each goat was housed separately in a metabolism cage for the entire experimental period of 21 days. <em>Lantana camara</em> leaf hay was incorporated in goat feed as a protein source at 5%, 10%, 15%, 20%, and 25% inclusion levels. Commercially bought, goat feed was used as the sixth and control treatment diet. Veld hay was used as a basal diet and water were offered <em>ad-libitum</em>. <strong>Results</strong>: The average daily dry matter intake was above the minimum recommended of 3% of the animal’s metabolic body weight (kg<sup>0.75</sup>). Goats fed on 10%LC consumed significantly lower quantities of hay than 5%LC but were not significantly different from goat feed (GF), 15%LC, 20%LC and 25%LC. Apparent digestibility coefficient values ranged from 62% to 71%. Higher nitrogen intakes was observed with diets that were highly palatable such as commercial goat feed and 5% <em>L. camara</em>. Higher microbial protein supply was observed in groups fed diets with high levels of <em>L. camara</em>. <strong>Implications:</strong> The use of invasive <em>L. camara</em> biomass as a source of goat feed at 5% inclusion is a promising method to control its spread in while addressing the nitrogen deficiencies experienced by livestock that subsist on poor quality feeds in invaded rangelands. <strong>Conclusion:</strong> Supplementing goats with <em>L. camara</em> leafy hay improves dry matter feed intake and degradability. Contrary to expectations, no negative effects were observed with <em>L. camara </em>leafy meal inclusion in goats diets at 5 to 25 percent inclusion level.</p>

Ethiopian indigenous goats offer insights into past and recent demographic dynamics and local adaptation in sub-Saharan African goats.

Knowledge on how adaptive evolution and human socio‐cultural and economic interests shaped livestock genomes particularly in sub‐Saharan Africa remains limited. Ethiopia is in a geographic region that has been critical in the history of African agriculture with ancient and diverse human ethnicity and bio‐climatic conditions. Using 52K genome‐wide data analysed in 646 individuals from 13 Ethiopian indigenous goat populations, we observed high levels of genetic variation. Although runs of homozygosity (ROH) were ubiquitous genome‐wide, there were clear differences in patterns of ROH length and abundance and in effective population sizes illustrating differences in genome homozygosity, evolutionary history, and management. Phylogenetic analysis incorporating patterns of genetic differentiation and gene flow with ancestry modelling highlighted past and recent intermixing and possible two deep ancient genetic ancestries that could have been brought by humans with the first introduction of goats in Africa. We observed four strong selection signatures that were specific to Arsi‐Bale and Nubian goats. These signatures overlapped genomic regions with genes associated with morphological, adaptation, reproduction and production traits due possibly to selection under environmental constraints and/or human preferences. The regions also overlapped uncharacterized genes, calling for a comprehensive annotation of the goat genome. Our results provide insights into mechanisms leading to genome variation and differentiation in sub‐Saharan Africa indigenous goats.

Dairy goat production in sub-Saharan Africa: current status, constraints and prospects for research and development.

This paper presents a review of dairy goat production in sub-Saharan Africa (SSA) from 2010–2017, its current state, constraints and prospects for research and development. Since the introduction of dairy goats in SSA in pre-colonial times, their populations have continued to increase due to declining land size as a result of land fragmentation and increasing demand for goat milk. The current goat population in SSA is 372,716,040 head of which only 15.98% used for milk production. Populations in the Eastern and Western regions of SSA have shown an increasing trend from 2010 to 2017. The Southern Africa goat population is on the decline at an annual rate of about 1.77% whereas Central Africa has had a constant goat population within the same period. Eastern Africa reported the highest increase in the population of goats used for milk production. Milk production was highest in Eastern Africa and lowest in Southern Africa. However, dairy goat productivity remained constant in the Eastern region throughout the review period. Dairy goats are mainly raised under smallholder mixed crop-livestock systems. To enhance the development of the dairy goat, concerted efforts should be made to alleviate the constraints that stifle its growth. These constraints can be categorized into nutrition and feeding, breeding and reproduction, diseases, parasites, climate change, and underdeveloped dairy goat products market. Effective management of dairy goats requires a holistic approach and there is the need to expand the markets by further sensitization on the nutritional and medicinal advantages of dairy goat products. In order to achieve rapid development in the dairy goat sub sector, research and development initiatives should be directed towards alleviating the hurdles in nutrition and feeding, breeding, animal health and resilience as well as dairy goat markets.

Morphometric Evaluation of Gross Pulmonary Indices in the Red Sokoto Goats for Pulmonary Consolidation Assessment

Goats are widely adapted to different climates and are found in all production systems. However, very little is known on the pulmonary morphometry of indigenous goats in Africa. The study aims to determine the standard morphometry and dimensions of the Red Sokoto RS goat lungs, which may serve as basis for clinical and radiographic assessment of pulmonary consolidation. The goats were sourced from a Municipal abattoir considering age and sex. A total of 35 non‐pneumonic RS lungs were collected including 22 males and 8 females, 6 between <1 years, 15 between 1–2 years and 9 > 2 years. Weight (gram), length (cm) and diameter (cm) of each lung lobe, distance from trachea bronchus to point of trachea bifurcation, distance between left and right trachea bifurcation were taken using standard measurements. The right lung contributes the most (61.67%) while the left lung contributes the least weight (38.32%). Of the 61.67% contributed by the right lung, the caudal lobe contributes 38.9% while the cranial (14.71%), middle (5.83%) and accessory (1.53%) lobes makes up the remaining. It was also discovered that the caudal lobe of the right lung contributes more than the left lung. The percentage contribution of right lung lobes increased with increase in age except for the accessory lobe which decreased with increasing age. The percentage contribution of the left lung lobes decreased with increasing age except for the middle lobe which was increasing with age. The right lung is longer (6.70±0.57) than the left lung (13.40±0.82). The right cranial lobe is longer and wider than the left cranial lobe. The right middle lobe is insignificantly longer (1.20±0.57) than the left (1.10±0.22) but significantly less wide (6.7±0.57) than the left (7.72±1.14). The right caudal lobe is longer (8.76±0.25) than the left (8.50±0.50) but less wider (4.86±0.20) than the left (5.5±0.61). The males have higher weight and dimensions than females except that the values of the right lung, the caudal lobe of the right lung and the middle lobe of the left lung are higher in females than in males. In conclusion, this study established the standard as regarding the normal size of each lung lobe and lobule in relation to the age and sex of the RS goat. These parameters will aid diagnosis of lung disease and assessment of pulmonary consolidation at postmortem in a poor resource setting.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Peste des Petits Ruminants Virus, Mauritania

Peste des Petits Ruminants Virus, Mauritania

Antibody response to Mycoplasma capricolum subsp. capripneumoniae bacterium in small holder dairy goats in Tanzania

Contagious caprine pleuropneumonia (CCPP), an Office International des Epizooties listed disease, can cause significant levels of morbidity and mortality in goats in Africa, the Middle East, and Western Asia. A cross-sectional study was conducted to determine the seroprevalence of CCPP, in two contrasting administrative districts of northern Tanzania, namely, Babati and Arumeru. A total of 337 serum samples were collected from January to July 2010, from apparently clinically healthy unvaccinated dairy goats breeds of different ages and sexes. Samples were subjected to monoclonal antibody-based competitive enzyme-linked immunosorbent assay for the specific measurement of antibodies to Mycoplasma capricolum subsp. capripneumoniae bacterium. The overall animal flock and village-level seroprevalence of CCPP was found to be 3.3 % [95 % confidence interval (CI) = 1.6-5.8], 9.6 % (95 % CI = 4.7-16.9), and 31.5 % (95 % CI = 15.6-56.5), respectively. There was no evidence (p = 0.659) of differences in seroprevalence between samples from the two administrative locations. Despite the fact that there was no significant difference (p > 0.05) in seropositivity between sex and age and between breeds sampled, there was a significant difference (p < 0.05) in seropositivity between the different physiological status groups examined with the non-lactating (dry) category of goats showing a higher seroprevalence. The findings of this survey revealed evidence of dairy goat exposure to M. capricolum subsp. capripneumoniae, although at a low prevalence. It is therefore advisable to include CCPP serology in the seromonitoring program so as to give a better indication of flock immunity. This should lead to the establishment of appropriate CCPP control measures in smallholder dairy goat flocks, which are increasingly being recognized for their value as a vital source of livelihood for resource poor livestock keepers in Tanzania.

Practical crossbreeding for improved livelihoods in developing countries: The FARM Africa goat project

Successful livestock improvement programmes focusing on low-input smallholder production systems though rare, are possible using community-based approaches. This paper outlines important design and implementation components of a goat improvement programme undertaken by FARM Africa in the eastern highlands of Kenya. Through strong capacity building initiatives at grass-roots level, producers were empowered to undertake a goat genetic improvement programme that benefitted them in several ways. This resulted in the farmers forming their own umbrella organizations to cater for their interests as producers in accessing animal health and breeding services, production inputs, and marketing goats and goat products. In seven years, the population of improved goats in one of the project areas increased from 2100 to 5500, and the livelihoods of the participating farmers improved. Income from sales of milk and improved breeding and slaughter stock increased, while food security improved as a result of daily milk consumption and improved crop yields resulting from use of the rich goat manure. The project has, however, faced challenges arising mainly from the popularity of the improved goats within the Eastern Africa region, which has resulted in sale of a large number of the young animals, leaving few replacements within the project area. Uptake of goat breeding by private commercial farmers to provide breeding stock and replacement animals is currently lacking. Further research and evaluation is required on how to strengthen collective-action based institutions to improve services within smallholder farmer communities.

Genetic polymorphism of kappa-casein gene in indigenous Eastern Africa goat populations

Indigenous goat breeds kept by majority of smallholder rural farmers in Eastern Africa are adapted to the local environment. These goats are critical for nutrition and income of their keepers. Milk production per doe is extremely variable. The variation in milk yield in goats is due to varied management practices and variability in genetic make-up of the animals. The variation in kappa-casein gene and the distribution frequencies of its variants amongst indigenous Eastern Africa goat populations were investigated. A 458 base pairs sequence in exon 4 of 296 goat samples were amplified, sequenced and variation analyzed. Nine point mutations corresponding to base transitions were identified. Three sites were synonymous substitutions while the other six mutations were non-synonymous. All the amino acid substitutions were conservative. Analysis of the association of the mutations yielded nine haplotypes. The occurrence of these haplotypes in ten goat populations indicated that only one haplotype occurred at a rather high frequency. The prevalent κ-casein variant was CSN3*B with frequencies ranging from 0.750 to 0.953. The second most common allele was CSN3*A. Further studies on other casein loci are necessary to establish associations of all the casein mutations and the effects of the haplotypes to milk production traits. Key words: Goat, indigenous, k-casein, polymorphism. Indigenous goat breeds kept by majority of smallholder rural farmers in Eastern Africa are adapted to the local environment. These goats are critical for nutrition and income of their keepers. Milk production per doe is extremely variable. The variation in milk yield in goats is due to varied management practices and variability in genetic make-up of the animals. The variation in kappa-casein gene and the distribution frequencies of its variants amongst indigenous Eastern Africa goat populations were investigated. A 458 base pairs sequence in exon 4 of 296 goat samples were amplified, sequenced and variation analyzed. Nine point mutations corresponding to base transitions were identified. Three sites were synonymous substitutions while the other six mutations were non-synonymous. All the amino acid substitutions were conservative. Analysis of the association of the mutations yielded nine haplotypes. The occurrence of these haplotypes in ten goat populations indicated that only one haplotype occurred at a rather high frequency. The prevalent κ-casein variant was CSN3*B with frequencies ranging from 0.750 to 0.953. The second most common allele was CSN3*A. Further studies on other casein loci are necessary to establish associations of all the casein mutations and the effects of the haplotypes to milk production traits. Key words: Goat, indigenous, k-casein, polymorphism.

Characterization of the Casein Gene Complex in West African Goats and Description of a New αs1-Casein Polymorphism

The analysis of casein polymorphisms was carried out in West Africa goat populations: Red Sokoto (n = 57), West African Dwarf Nigeria (n = 27), West African Dwarf Cameroon (n = 39), and Borno (n = 37). The 4 casein genes αs1 (CSN1S1), β (CSN2), αs2 (CSN1S2), and κ (CSN3) were typed at the DNA level. No null alleles were found in any of the genes analyzed. A PCR single-strand conformation polymorphism method was implemented for the identification of CSN1S1*F allele simultaneously with A/01, B/E, N and the new allele. The allele differed from CSN1S1*B by a synonymous transversion TCG→TCT in the codon corresponding to Ser66 of the mature protein. The new allele, named CSN1S1*B′, occurred at a high frequency in all the populations, ranging from 0.295 (West African Dwarf Cameroon) to 0.405 (Borno). A greater frequency was found for alleles associated with high αs1-casein quantity, as has already been observed in the goat populations from the Mediterranean area. The intermediate E allele occurred only in the Red Sokoto and at a low frequency. The faint F allele occurred in 3 populations at frequencies lower than 0.03. Linkage disequilibrium occurred in all the populations, with highly significant differences in Borno, Red Sokoto, and West Africa Dwarf Nigeria, and significant differences in West Africa Dwarf Cameroon. Only 10 haplotypes showed frequencies ≥0.05 in at least 1 of the 4 populations considered, and the overall frequency was >0.1 only for 4 haplotypes: BAAB, B′ACA, ACAB, and BACA (in the order CSN1S1-CSN2-CSN1S2-CSN3). Haplotype BAAB, postulated as an ancestral haplotype in previous studies, was the most common haplotype in all breeds except Borno, where B′ACA was predominant. The results obtained are of considerable significance given that very little information exists on the subject for African goats. The high frequency of strong alleles in the calcium-sensitive caseins as well as the high linkage disequilibrium found among the casein genes in the African breeds analyzed may suggest that specific casein haplotypes have already been selected due to their advantages for nutrition. Haplotypes providing greater protein and casein content would increase the energy content of milk, thus resulting in more favorable growth and survival of young goats and humans consuming the milk.

Trypanosomosis in Goats

Trypanosomosis is a major constraint on ruminant livestock production in Africa, Asia, and South America. The principal host species affected varies geographically, but buffalo, cattle, camels, and horses are particularly sensitive. Natural infections with Trypanosoma congolense, T. vivax, T. brucei, and T. evansi have been described in goats. Trypanosomosis in goats produces acute, subacute, chronic, or subclinical forms, being T. vivax, T. congolense, and T. evansi, the most invasive trypanosomes for goats. However, the role of goats in the epidemiology of trypanosomosis is largely discussed and not well understood. Thus, it has commonly been assumed that trypanosomosis presents a subclinical course and that goats do not play an important role in the epidemiology of the disease. This can partially be due to parasitemia caused by trypanosomes which has been considered low in goats. However, this assumption is currently undergoing a critical reappraisal because of goats may also serve as a reservoir of trypanosome infection for other species, including the human beings in the case of T. brucei rhodesiense. The present article describes the current status of trypanosomosis in goats in Africa, Asia, and South America. Pathogenesis, clinical features, diagnosis, and treatment of the different trypanosomes are also described. The possible role in the epidemiology of the disease in the different areas is also discussed.

A specific PCR for the identification of Mycoplasma capricolum subsp. capripneumoniae, the causative agent of contagious caprine pleuropneumonia (CCPP)

Contagious caprine pleuropneumonia is a severe infectious disease of goats in Africa and the Middle East. It is caused by a fastidious mycoplasma, Mycoplasma capricolum subsp. capripneumoniae, a member of the “ M. mycoides cluster”. Members of this cluster share genomic and antigenic features, which result in common biochemical and serological properties, complicating species identification. Two species of this cluster, M. mycoides subsp. capri and M. mycoides subsp. mycoides large colony biotype, are very often isolated from clinical cases resembling contagious caprine pleuropneumonia. Furthermore, in the laboratory, M. capricolum subsp. capripneumoniae can be easily confused with the closely related capricolum subspecies. Considering these constraints and the scarcity of available methods for identification, a specific polymerase chain reaction was developed. A DNA fragment of 7109 bp containing genes coding for the arginine deiminase pathway (ADI) was chosen as target sequence for the selection of a specific primer pair. The full ADI operon from M. capricolum subsp. capripneumoniae strain GL100 was sequenced. Polymorphism within this locus was analyzed by comparison with the sequence from the closely related IPX strain ( M. capricolum subsp. capricolum). It varied from 0.6% to 3.5%. The highest divergence was found in a region coding for arcD. Therefore, this gene was chosen as target for the specific amplification of a 316 bp-long DNA fragment. The specificity of this PCR was validated on 14 M. capricolum subsp. capripneumoniae strains and 27 heterologous strains belonging to the “ M. mycoides cluster” and M. putrefaciens. This new PCR will be a valuable tool for the surveillance of contagious caprine pleuropneumonia.

Nairobi Sheep Disease Virus, an Important Tick-Borne Pathogen of Sheep and Goats in Africa, Is Also Present in Asia

Nairobi sheep disease (NSD) virus is the prototype of the tick-borne NSD serogroup, genus Nairovirus, family Bunyaviridae. It is highly pathogenic for sheep and goats, causes disease in humans, and is widespread throughout East Africa. Ganjam virus has caused disease in goats and humans in India. Due to their occurrence on different continents and association with different ticks, these viruses were considered distinct despite serologic cross-reactivity. Their S RNA genome segments and encoded nucleocapsid proteins were found to be 1590 nucleotides and 482 amino acids in length and differed by only 10 and 3% at nucleotide and amino acid levels, respectively. Genetic and serologic data demonstrate that Ganjam virus is an Asian variant of NSD virus. These viruses were phylogenetically more closely related to Hazara virus than Dugbe virus.

Multiparasitism in Sub-Saharan West African Countries: Don't Forget the Least Important!

In a recent issue of Parasitology Today[1xZinsstag, J. et al. Parasitol. Today. 1998; 14: 46–49Abstract | Full Text | Full Text PDF | PubMed | Scopus (15)See all References][1], Jakob Zinsstag et al. gave us a very nice review on the epidemiology and economic weight of gastrointestinal parasites of sheep and cattle in West Africa. This work includes the observations of the efficient young West African researchers network that Pfister and Zinsstag developed. However, some comments have to be made because multiparasitism is often not taken into account.A few years ago, during the WAAVP meeting held in Yokohama, Japan, Peter Hansen (Abstract)1P. Hansen, Tropical livestock industry: parasite control, food security and the environment. Proceedings, 15th International Conference of the World Association for the Advancement of Veterinary Parasitology, Yokohama, Japan, 1995, p. 551 stressed the impact of `secondary' pathogens. The extensive campaigns against Rinderpest, trypanosomiasis, etc. have utilized funds, therefore causing a shortage of money with which to fight against strongyles, flukes, etc. These pests are not often `serial killers', but their pathogenic weight is high. To establish prevalence of some of them, and evaluate their importance, we performed sero-epidemiological surveys in sheep and goats in Africa using indirect haemagglutination assay for Toxoplasma[2xDorchies, P. et al. Revue de Medecine Veterinaire. 1996; 147: 377–378See all References][2]and by a specific ELISA (enzyme-linked immunosorbent assay) for CEstrus ovis (P. Dorchies, Abstract)2P. Dorchies et al. (1997) Proceedings, 16th International Conference of the World Association for the Advancement of Veterinary Parasitology, Sun City, South Africa, 1997, p. 212.Table 1Table 1 (Ref. [2xDorchies, P. et al. Revue de Medecine Veterinaire. 1996; 147: 377–378See all References][2]) shows that toxoplasmosis may be a serious threat in African countries mainly in wet areas. Toxoplasmic ovine abortion is frequent in some countries such as the UK, but the situation in Africa is not well known. Moreover, this infection may be serious for the babies of young women. Some correlation has been observed between human and animal seroprevalence as both are exposed to the same risk.Table 1Seroprevalence of ovine toxoplasmosis in AfricaaCountrySera, NbPositive (%)Burkina Faso6523Ivory Coast6268Djibouti18312.6Ethiopia9425.6Niger7719.5Senegal5211.5 View Table in HTML aData from Ref. [2xDorchies, P. et al. Revue de Medecine Veterinaire. 1996; 147: 377–378See all References][2].Sheep nasal bot is another example of a widespread parasite, and is so frequent that its pathological weight is difficult to evaluate. Sheep or goats mouth-breathing is a common sight during the dry season because nasal discharge cakes with dust on the nostrils. This is known by vets or breeders to be related to pasteurellosis: of course, but the infection is secondary to CEstrus ovis infection. Because the CEstrus ovis infection results in impairment of grazing and rumination, a local but not very pathogenetic parasite can have a serious economic weight.Parasitologists are increasingly aware that one of the most important threats due to helminths and arthropods is related to immunomodulation. The permanent challenge to the immune system increases the susceptibility of the animal to viral and bacterial diseases that finally kill it. If we want sustainable development of breeding in many countries we have to be aware of the weight of these `small' parasites.In their paper, Zinsstag et al.[1xZinsstag, J. et al. Parasitol. Today. 1998; 14: 46–49Abstract | Full Text | Full Text PDF | PubMed | Scopus (15)See all References][1]did not stress the impact of helminth circulation among grazing animals[3xJacquiet, P. et al. Int. J. Parasitol. 1998; 26: 253–261Crossref | Scopus (24)See all References][3]. Some recent papers deal with the importance of host range (sheep, goats, cattle and camels) in the survival of Homonchus spp in Africa. Parasites may survive as adults or as hypobiotic larvae in specific hosts (eg. H. contortus in sheep, H. placei in cattle and H. longistipes in camel), but also in nonspecific hosts (eg. H. longistipes in goats, H. placei in sheep). These facts have to be taken into account when a drenching program is planned.These examples confirm once again the impact of `secondary' pests that, in some cases, may represent serious health threats.

Development and distribution of rinderpest virus antigen in experimentally infected goats.

Three goats, experimentally infected with rinderpest virus were examined for the development and distribution of precipitating antigens in various tissues and secretions using the agar gel immunodiffusion test. Virus antigens were detected in ocular secretions and lymph node biopsies from the second to the fourth and fifth days of pyrexia, respectively, but were not detected in nasal secretions. Precipitating antigens were demonstrated in various lymphoid organs, the lung and abomasum of a goat killed on the fourth day of pyrexia. These findings are discussed in relation to the epidemiology of rinderpest in goats in Africa.