Circulating Brucella species in wild animals of the Serengeti ecosystem, Tanzania.

BACKGROUND: Brucellosis is a bacterial zoonosis of public health and economic importance worldwide. It affects a number of domestic animals, wild animals and humans. Human brucellosis originates from either livestock or wildlife. The species of Brucella circulating in wild animals in Tanzania is largely unknown due to insufficient surveillance. This study was carried out to identify Brucella species found in selected wildlife hosts in the Serengeti ecosystem. METHODOLOGY: The study used a total of 189 archived samples that were obtained from cross-sectional studies previously conducted between 2000 and 2017 in the Serengeti ecosystem in Tanzania. Whole blood, serum and amniotic fluid collected from buffalos, lions, wildebeest, impala, zebra and hyena were available for DNA extraction. Multiplex polymerase chain reaction for B. abortus, B. melitensis, B. ovis and B. suis (AMOS PCR) and quantitative real-time PCR (qPCR) targeting the bcsp31 and IS711 genes for Brucella genus detection and the IS711 targets alkB for B. abortus and BMEI1162 for B. melitensis were used to detect Brucella strains. RESULTS: Out of the 189 samples tested, 12 (6.35 %) and 22 (11.6 %) were positive to AMOS-PCR and qPCR, respectively. Most of the positive samples were from lions (52.6 %) and buffaloes (19.6 %). Other animals that were positive included: wildebeest (13.6 %), impala (13.6 %), zebra (4.5 %) and hyena (4.5 %). Out of 22 positive samples, 16 (66.7 %) were identified as B. abortus and the other six samples did not amplify for neither B. abortus nor B. melitensis. CONCLUSIONS: The detection of Brucella DNA in archived wild animal samples shows testing potential of samples collected from this population. The zoonotic species B. abortus and B. melitensis detected in wild animals have previously been reported in livestock and humans in the region. The findings suggest that, due to the contact network, some of the identified wild animal hosts in this study could be reservoirs for infections in domestic animals and humans within the Serengeti ecosystem while others are likely dead-end hosts. One Health control strategies and continuous surveillance programs in other wildlife reserved areas should be implemented to help predicting transmission in livestock and humans in the region.

Isolation and Potential for Transmission of Mycobacterium bovis at Human-livestock-wildlife Interface of the Serengeti Ecosystem, Northern Tanzania.

Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is a multihost pathogen of public health and veterinary importance. We characterized the M. bovis isolated at the human-livestock-wildlife interface of the Serengeti ecosystem to determine the epidemiology and risk of cross-species transmission between interacting hosts species. DNA was extracted from mycobacterial cultures obtained from sputum samples of 472 tuberculosis (TB) suspected patients and tissue samples from 606 livestock and wild animal species. M. bovis isolates were characterized using spoligotyping and Mycobacterial Interspersed Repetitive Units-Variable Tandem Repeats (MIRU-VNTR) on 24 loci. Only 5 M. bovis were isolated from the cultured samples. Spoligotyping results revealed that three M. bovis isolates from two buffaloes (Syncerus caffer) and 1 African civet (Civettictis civetta) belonged to SB0133 spoligotype. The two novel strains (AR1 and AR2) assigned as spoligotype SB2290 and SB2289, respectively, were identified from indigenous cattle (Bos indicus). No M. bovis was detected from patients with clinical signs consistent with TB. Of the 606 animal tissue specimens and sputa of 472 TB-suspected patients 43 (7.09%) and 12 (2.9%), respectively, yielded non-tuberculous mycobacteria (NTM), of which 20 isolates were M. intracellulare. No M. avium was identified. M. bovis isolates from wildlife had 45.2% and 96.8% spoligotype pattern agreement with AR1 and AR2 strains, respectively. This finding indicates that bTB infections in wild animals and cattle were epidemiologically related. Of the 24 MIRU-VNTR loci, QUB 11b showed the highest discrimination among the M. bovis strains. The novel strains obtained in this study have not been previously reported in the area, but no clear evidence for recent cross-species transmission of M. bovis was found between human, livestock and wild animals.

Stakeholders in One Health.

The stakeholders in One Health include the ultimate beneficiaries (i.e. animals, people and the environment) and the organisations that work to protect them (i.e. research institutes, government ministries, international organisations and professional bodies). However, identifying these stakeholders who will contribute to One Health activities and develop solutions to complex health problems can be difficult, as these problems often affect all sectors of society. In addition, evolving concepts about health and its dependence on environmental resilience necessitate the inclusion of ministries, organisations and disciplines that may not have been traditionally considered to be related to health. The multilateral organisations with greatest responsibilities in the global health arena have recognised that the best way to protect health security and promote overall global well-being is to work together across disciplinary and jurisdictional boundaries. Permanent regional networks and ad hoc networks created to tackle specific issues (both of which require donor investment) are also facilitating improved disease surveillance and collaborative approaches to synchronised interventions across country borders. These networks necessarily involve the key ministries for One Health, those of health, agriculture/livestock, and natural resources/environment. Ministries play a critical role in the formulation and implementation of policies for the promotion of health and disease control. They contribute to all stages of the One Heath process, as do universities, which engage by generating knowledge and capacity through teaching, research and extension services. Similarly, non-governmental organisations have a key role in stewardship; resource mobilisation; generation of knowledge; capacity development; intervention design; and implementation. Finally, communities, including rural and indigenous peoples, particularly those that are in close proximity to natural areas, are at the heart of the One Health concept.

Effectiveness of a community-based strategic anthelmintic treatment programme in the control of gastrointestinal nematodes and Fasciola gigantica in cattle in Kilolo district, Tanzania.

A longitudinal demonstration project was carried out in 2005/2006 for thirteen months to determine the effectiveness of a strategic community-based worm control (CBWC) programme in the control of gastrointestinal (GI) nematodes and Fasciola gigantica in cattle. Two villages namely, a CBWC village (Ilula-Masukanzi) and a village without CBWC (Kilolo-Luganga) were randomly selected in Kilolo district, Iringa region of Tanzania. Animals in both villages were under the traditional management system and used the village communal grazing area. At the village with CBWC, 60 zebu cattle (6-18 months old) from 10 farms in the village were selected and ear tagged for monthly sampling and weghing. A strategic CBWC programme was instituted whereby all animals in the village (tagged and non-tagged) were treated with albendazole 10% drench at 10 mg/kg four times a year e.g. middle of the rainy season (February), end of the rainy season (May), middle of the dry season (September) and late dry/early rainy season (December). In the village without CBWC, 68 zebu cattle (6-18 months old) from 11 farms in the village were selected and tagged for monthly sampling and weighing. Farmers in the village without CBWC were allowed to continue with their normal management practices including anthelmintic treatments. Faecal and blood samples from tagged animals and pasture samples from communal grazing areas were collected on monthly basis for 13 months. Results showed that strategic CBWC programme was highly effective in reducing faecal egg counts (FEC) and the proportion of animals passing Fasciola eggs in faeces. The strategic CBWC significantly reduced FEC of animals by an average of 60% compared to animals at the village without CBWC (P < 0.01). Four strategic CBWC treatments per year significantly reduced the proportion of animals passing Fasciola eggs in faeces by an average of 82.5% compared to animals at the village without CBWC (P < 0.05). From commencement to the end of the trial, animals at the village with CBWC significantly outgained animals at the village without CBWC by an average of 13.9 kg per year (P < .05). It is concluded that strategic CBWC programme was highly effective in reducing FEC, reducing the proportion of animals passing Fasciola eggs in faeces and improved weight gain in animals.

Effectiveness of strategic anthelmintic treatments in the control of gastrointestinal nematodes and Fasciola gigantica in cattle in Iringa region, Tanzania.

A longitudinal field trial was conducted to determine the effectiveness of strategic anthelmintic treatments in the control of gastrointestinal (GI) nematodes and Fasciola gigantica in cattle. A total of 167 cattle (6-18 months) from three large-scale dairy farms, four traditional farms and nine small-scale dairy farms were randomly selected. The selected animals on each farm were ear tagged and allocated into three groups based on live weight and treated as follows: Group T4 was treated with albendazole 10% drench at 10 mg/kg four times a year (mid rainy, end of the rain, mid dry and late dry/early rainy season). Group T2 was treated with albendazole 10% drench at 10 mg/kg two times a year (mid rainy and late dry/early rainy season). Group UT remained as untreated control. Faecal, blood and pasture samples were taken every month for 13 months. In addition, individual body weight (BWT) was measured on every sampling date. Results showed that two and four strategic treatments significantly reduced faecal egg counts (FEC) by 49.5% and 62.3% respectively compared to untreated control animals (P < 0.001). Two and four strategic treatments per year significantly reduced the proportion of animals passing Fasciola eggs in faeces by 30.6% and 51.7% (P < 0.001), respectively. Animals treated two and four times a year significantly outgained untreated animals by 14.8 kg and 17.7 kg respectively at the end of the trial (P < 0.05). The management system had a significant effect on packed cell volume and the proportion of animals passing Fasciola eggs in faeces (P < 0.05). The programme of two strategic treatments per year was only effective in controlling GI nematodes. It is concluded that a programme of four strategic treatments per year was effective in controlling GI nematodes and F. gigantica and improved weight gain.

Cross-sectional prevalence of helminth infections in cattle on traditional, small-scale and large-scale dairy farms in Iringa district, Tanzania.

A cross-sectional study was carried out to determine the prevalence of gastrointestinal (GI) nematodes and flukes (Fasciola and amphistomes) infection in communally grazed traditional cattle, zero-grazed small-scale dairy cattle and intensively grazed large-scale dairy cattle through examination of helminth eggs in faeces. Results indicated that the type of management, especially the grazing habit, has a significant influence on the prevalence and intensity of GI nematodes and flukes. The prevalence of GI nematodes in traditional, large-scale dairy and small-scale dairy cattle was 67%, 44.4% and 37%, respectively, with the highest faecal egg counts in calves. The overall prevalence of Fasciola gigantica in traditional, large-scale dairy and small-scale dairy cattle was 63.8%, 46.2% and 28.4%, respectively. The prevalence of amphistomes was 81.9%, 55.5% and 41.1% in traditional, large-scale dairy and small-scale dairy cattle, respectively. The high prevalence of flukes in the traditional system was attributed to communal grazing and watering management practices. Stomach flukes recovered in examined cattle at the abattoir were Calicophoron microbothrium and Cotylophoron jacksoni. About 42.1% of infected animals had both Fasciola and amphistomes. The prevalence of both GI nematodes and flukes varied greatly among villages and farms. The prevalence of both Fasciola and amphistomes was higher in adults (58.5%, 75.2%) than in yearlings (36.5%, 51.5%) or calves (24.9%, 47.2%). The variation in the prevalence of both GI nematodes and flukes among management and age groups within systems can be used as an entry point towards rational use of anthelmintics for each management system. More studies on seasonal transmission pattern of all these parasites are required in order to design rational, economic and locally sustainable parasite control programmes.

Epidemiology of Fasciola gigantica and amphistomes in cattle on traditional, small-scale dairy and large-scale dairy farms in the southern highlands of Tanzania.

A longitudinal descriptive study was conducted to determine the prevalence and distribution of flukes (Fasciola gigantica and amphistomes) on traditional, large-scale and small-scale dairy cattle farms in Iringa district, southern highlands of Tanzania. Coprological examinations of different cohorts for the presence of fluke eggs were recorded monthly. Results indicated a significant influence of the type of management on the prevalence of both Fasciola and amphistomes. The prevalence of flukes was highest in the traditional system, moderate in the large-scale dairy system and lowest in the small-scale dairy system in most parts of the year. Adults and yearlings had the highest prevalence of flukes in all management systems throughout the year. The proportion of animals excreting amphistome eggs was always higher than that of animals excreting Fasciola eggs in all zones, villages, management systems, farms and age groups. The proportion of animals passing fluke eggs increased gradually from the early dry season and peaked at the end of the dry season and the early part of the rainy season. Strategic treatments against flukes are recommended in adults and yearlings only in traditional and large-scale dairy farms. Routine treatments of calves/weanlings in large-scale and traditional farms and zero-grazed small-scale dairy cattle farms might be unnecessary. For a cost-effective helminth control programme in the area, strategic treatments at the beginning of the dry season (June) and at the end of the dry/early rainy season (November/December) are recommended.

Epidemiology of gastrointestinal nematodes in cattle on traditional, small-scale dairy and large-scale dairy farms in Iringa district, Tanzania.

A longitudinal study was carried out to determine the prevalence, distribution and intensity of gastrointestinal (GI) nematodes in traditional, small-scale dairy and large-scale dairy cattle farms in Iringa district, Southern highlands of Tanzania. Coprological examination of cohorts for GI nematode eggs in faeces, tracer worm counts and pasture larval counts were performed monthly for 1 year. Results indicated that the type of management, especially the grazing habit has a significant influence on the prevalence and intensity of GI nematodes. The predominant nematodes were Cooperia spp. (51.6%), Oesophagostomum radiatum (35.7%) and Haemonchus placei (10.2%). The worm burden in tracers was mainly composed of Cooperia spp. (83%) in large-scale dairy farms, while O. radiatum was dominant (60.8%) in traditional farms. Faecal egg counts (FEC) and tracer worm counts were generally low and FEC peaked only in calves and weaners/yearlings. Adults and all age groups in small-scale dairy farms had very low FEC throughout the year. Pasture larval counts, FEC and tracer worm counts peaked towards the end of the rainy season. Based on conditions of the study area, farmers could save substantial amount of money through strategic treatments as opposed to the previous routine of treating the whole herd at least four times a year. Strategic treatments are recommended in calves and weaners only in traditional and large-scale dairy farms. Strategic treatment of adults and small-scale dairy cattle might be not necessary. Strategic treatments at the end of the rainy/early dry season (May/June) and at the end of the dry/early rainy season (November/December) are recommended in the district. An additional treatment against GI nematodes in calves during the mid rainy season (February/March) might be important.

Gastrointestinal nematodes in indigenous Zebu cattle under pastoral and nomadic management systems in the lower plain of the southern highlands of Tanzania.

This study aimed to determine the prevalence and intensity of gastrointestinal nematode infections in indigenous Zebu cattle in the lower plain (lowland zone) of the southern highlands of Tanzania. Gastrointestinal tracts were randomly purchased at the Iringa regional abattoir and at Kihesa and Ipogolo slaughter slabs in different seasons of the year. The contents of the abomasum, small intestine and large intestine were processed separately to recover the worms. The results indicated that 140 out of 144 (97.2%) of the examined animals were infected. The mean (+/-SE) total worm burden was 1284 +/- 183 (range 10-12,600) worms per animal and most infected animals contained more than one nematode species. The nematode species present, their prevalence and mean burden were as follows: Haemonchus placei, 84.7%, 316; H. similis, 5.6%, 1; Oesophagostomum radiatum, 79.2%, 66; Cooperia pectinata, 55.6%, 713; C. punctata, 44.4%, 157; Bunostomum phlebotomum, 5.6%, 5; Trichuris globulosa, 5.6%, 2; and Trichostrongylus colubriformis, 1.4%, 24. The burdens were mainly composed of Cooperia pectinata (55.5%), Haemonchus placei (24.6%), Cooperia punctata (12.3%) and Oesophagostomum radiatum (5.1%). The highest burdens occurred at the end of the rainy/early dry season, while the lowest burdens were found at the end of the dry/early rainy season. There was no difference in the burdens between male and female animals. Immature cattle (< 3 years) had significantly higher worm burdens than mature cattle (p < 0.01). A poor grade for a live animal was associated with higher worm burdens only in immature cattle and then especially during the dry season (r = 0.456, p < 0.001). Anthelmintic treatments in the late rainy/early dry season and early rainy season are recommended in order to prevent outbreaks of helminthosis during the dry season and to reduce carryover of infection into the next rainy season. An additional wet season treatment is advisable in immature cattle, but may not be needed for mature cattle owing to the availability of plenty of mature, good quality pasture.

Worm control practices and anthelmintic usage in traditional and dairy cattle farms in the southern highlands of Tanzania.

Worm control practices and anthelmintic usage in 177 cattle farms in Iringa district in the southern highlands of Tanzania was determined through a questionnaire survey. A total of 76 traditional, 92 small-scale dairy and 9 large-scale dairy cattle farms were included in the survey. Results indicated that 87.7% traditional, 97.8% small-scale dairy and 100% large-scale farmers relied solely on the use of anthelmintics, 2.7% traditional farmers used traditional medicines while 9.6% traditional farmers had not any form of worm control practice. Worm infection was ranked the second most important constraint of productivity in cattle in the three production systems. Most farms (57.6% traditional, 35.8% small-scale dairy, 66.7% large-scale dairy) used anthelmintics with a combination of levamisole and oxyclozanide. Benzimidazoles were used only in traditional (25.4%) and small-scale dairy (32.1%) farms while nitroxynil (Trodax) was mostly used in large-scale dairy farms (33.3%). Generally, 40% of farmers treated three or four times a year and the frequency in some farms was surprisingly high for resource poor small-scale farmers. The frequency of anthelmintic treatment was mostly the same regardless of the management system. Treatments in most farms depended on availability of money and drugs and not the epidemiology of parasites. A significant proportion (46.3%, P=0.007) of farmers especially in rural areas failed to follow their pre-planned treatment schedules due to lack of money (86%) and unavailability of drugs (6.6%). Many farmers (58.9%) had used the same type of anthelmintic for four or more consecutive years and 85.3% of them would continue with the same anthelmintic. Farmers in all management systems mostly purchased anthelmintics from private veterinary drug shops and about 43% traditional and 33.3% small-scale dairy farmers mostly in rural areas obtained anthelmintics from village extension officers. Despite the fact that all farmers were aware of worm infection and the associated signs in cattle, 42.5% had poor knowledge on the source of worm infection. Small-scale dairy farmers allowed only a 1-day withdraw period for milk regardless of the type of anthelmintic used and there was no milk and slaughter clearance in traditional farms. It was concluded from this study that worm control in Iringa faces serious constrains and that education of farmers and farm hands is not adequate. Moreover, poor quality control and high price of potent anthelmintics, few extension workers, low income and low education among farmers contributed significantly to erratic worm control practices and anthelmintic usage in peri-urban and rural areas.

Distribution and density of cysticerci of Taenia solium by muscle groups and organs in naturally infected local finished pigs in Tanzania.

The distribution and density of cysticerci of Taenia solium among distinct carcass sites was determined in 24 naturally infected finished pigs from Mbulu district, Tanzania. The heart, tongue, internal and external masseters, triceps brachii, lungs, liver, kidneys, psoas, diaphragm and brain of each pig as well as the muscles from the forelimb, hind limb, abdomen, head and thorax from one half of each pig carcass were all designated as distinct carcass sites and sliced in such a way that all fully developed cysts could be revealed and enumerated (i.e. each slice was less than 0.5 cm thick). The carcasses harboured from 76 to 80,340 cysts in total. Carcass sites which harboured the highest proportion of cysts were those of the hind and forelimbs (mean: 27.7 and 24.5%, respectively, of the total cysts in the carcass), while lower proportions were found in the tongue, heart, triceps brachii, and diaphragm (7, 3.6, 2 and 2, respectively). Relative cyst density was calculated for the different carcass sites by dividing the mean proportion of the total weight of the tissue groups into the mean proportion of cysts located in that site. The cysticerci in the examined distinct carcass sites were found in the following order of relative density: psoas muscles (10.5), internal masseter (8.1), external masseter (7.1), triceps brachii (4.9), forelimb (4.0), head muscles (3.8), tongue (3.4), hind limb (3.2), diaphragm (2.4), heart (1.9), abdominal muscles (1.3), trunk muscles (1.1), brain (1.0) and oesophagus (0.3). The proportion of cysts expected to be found at the surfaces exposed by visual examination or incision at meat inspection was calculated using an indirect method, which incorporated the area revealed by incision and visual inspection of an organ and the proportion of cysts located in the particular organ. It was estimated that 10.6% of the cysts would be located at inspected sites if regulations were followed carefully.

Efficacy of albendazole and levamisole against gastrointestinal nematodes of sheep and goats in Morogoro, Tanzania.

A study was conducted to determine the efficacy of albendazole after it had been withdrawn from use due to the development of resistant strains of nematodes about ten years ago. The study also aimed to determine the present efficacy of levamisole, which had been recommended to replace albendazole. On one farm, the sheep and goats were divided into two groups, one group of each serving as the untreated control, while the other was treated with levamisole. The sheep on the other farm were divided into three groups, one serving as the untreated control group, the second being treated with levamisole and the third being treated with albendazole. Faecal samples were collected one day before treatment, and again 10 days after treatment. Anthelmintic efficacy was determined by the faecal egg count reduction test. Ten days after treatment, the sheep treated with levamisole on the first farm had a 98% reduction in faecal egg count, with a 95% confidence limit of 76%. The goats on the same farm had a 97% reduction in faecal egg count, with a 95% lower confidence limit of 81%. At the second farm, 10 days after treatment, sheep treated with levamisole had a 99.4% reduction in faecal egg count, with a 95% lower confidence limit of 88.9%, whereas the sheep treated with albendazole only had a 59.4% reduction in faecal egg count, with a 95% lower confidence limit of -19.6%. The study indicated that the gastrointestinal nematodes of sheep at the Department of Animal Science and Production farm were still resistant to albendazole about ten years after this anthelmintic had been withdrawn from use. A reduced efficacy of levamisole was suspected.

Peri-parturient helminthosis in strains of small East African goats in Tanzania.

The effect of physiological status (e.g. pregnancy and lactation) on the susceptibility to gastrointestinal nematodes was studied in the Dodoma and Kigoma strains of small East African goats in Morogoro. Forty-six pregnant does (19 Dodoma and 27 Kigoma strain) and 123 non-pregnant/dry (68 Dodoma and 55 Kigoma) from a controlled-breeding programme were used. Does were grazed on naturally contaminated pastures at Sokoine University of Agriculture for 8 months. Faecal samples and whole blood for determination of faecal egg counts (FEC), packed-cell volume (PCV) and blood eosinophils (EOS) from each animal were collected at monthly intervals from the mating period (through the gestation period) to 3 months after kidding. From kidding to 3 months after kidding, lactating does had significantly higher FEC than non-lactating/dry does. From 1 month after kidding to 3 months after kidding, lactating does had significantly lower PCV than dry does. Blood eosinophils were higher in non-lactating/dry does than lactating does but only significant at 3 months after kidding. There were no significant differences in FEC, PCV and EOS between lactating Dodoma and lactating Kigoma does. We concluded that there was no difference in peri-parturient helminthosis between Dodoma and Kigoma strains and that blood eosinophilia decreased during peri-parturient helminthosis in both strains.