Sero-prevalences of selected cattle diseases in the Kafue flats of Zambia

Sera from five traditionally managed herds grazing in the Kafue flats were tested for antibodies to bovine viral diarrhoea-mucosal disease (BVD-MD), parainfluenza 3 (PI3), infectious bovine rhinotracheitis-infectious pustular vulvovaginitis (IBR-IPV), bovine adenovirus 3 (BAV3) and Bluetongue (BT). The sero-prevalences of the first four diseases were respectively 76.2, 94.4, 42.1 and 87.4%. Five samples (2.3%) gave doubtful reactions for BT. Prevalences of 28.5% for brucellosis, 14% for Rift Valley fever (RFV), 0.9% for Q fever and 11.2% for chlamydiosis were also recorded. Significantly higher values for BVD-MD (p<0.005), IBR-IPV (p<0.01) and brucellosis (p<0.05) were found in animals over 1 year of age. No differences were recorded between herds or between male and female animals.The high concentration of wild and domestic ruminants grazing together in the flood plains during the dry season may be a major determinant of the high values observed. Traditional farmers, slaughterhouse workers and other people involved in livestock production are particularly at risk of contracting brucellosis and RVF because of the high prevalences in cattle and local habits favourable to their transmission.     

Predation on Large Mammals in the Kafue National Park,Zambia

Clymene dolphins, Stenella clymene, are endemic to the tropical and subtropical Atlantic Ocean, where their occurrence is documented from fewer than 200 records. The species is particularly poorly known in the eastern Atlantic off the coast of Africa where only 12 verified records exist, predominantly comprising dead animals. Marine mammal survey work was carried out off central West Africa during 2004 and 2005, producing two new observations of freeranging Clymene dolphins. Both sightings occurred in deep-water (466 and 684 m) over the shelf edge, off northern Angola and Congo respectively. A pod of 250 Clymene dolphins was observed off Congo, while the Angola sighting was of a mixed-species group of 12 Clymene dolphins with common dolphins, Delphinus sp. These records represent the first confirmed presence of Clymene dolphins off Angola and Congo, and extend the known southern limit of the confirmed distribution range of this species in the South-East Atlantic to 06°26‘S.     

The Stomach of the Kafue lechwe (Kobus leche kafuensis)

The Kafue lechwe is endemic to the Kafue Flats area of Zambia. It is semi-aquatic in habit, feeding upon grasses above and below the waterline. The volume of the lechwe rumen is 17 L in the male and 14 L in the female. It has strong and definite pillars. The interior of the rumen is papillated except in the roof area and on the pillars. The omasum has more than 70 laminae which are papillated on the reticular end. The anatomy of the lechwe stomach is similar to the stomachs of other water dependent grazers such as Bohor Reedbuck, Waterbuck, Uganda Kob and Puku.     

Seasonal pattern of bovine fasciolosis in the Kafue and Zambezi catchment areas of Zambia

In order to establish seasonality of bovine fasciolosis in the Southern province of Zambia, 288 cattle were examined at slaughter at Turnpike slaughter slab for 1 year. The examination involved liver inspection and coprological examination. Liver condemnation rates were relatively high at the beginning of both the cold dry season and the rainy season (May/June and December, respectively). All cattle, regardless of age, had higher fluke abundances in the post-rainy season (39.1% young and 42.1% adult) while the lowest rates were in the hot dry season (13.3% young and 14.3% adult). On coprological examination, the highest abundance was in the post-rainy season (45.0%) and the lowest in the cold dry season (24.9%). From November (end of dry season) to February/March (end of rains), more fluke eggs were found than in any other period. The distribution of fluke eggs was significantly different (p<0.001) among the four seasons. Identified associations were: egg counts were highest in post-rainy (mean abundance=146) and lowest in cold dry season (mean abundance=118) at 95% confidence (CI 0.64-1.25). Differences in abundance observed according to origin, sex and age of cattle were not significant on both methods. Based on these results, it may be concluded that Fasciola gigantica was present throughout the year in cattle in Zambia but the abundance was highest in the post-rainy season and lowest in the cold dry season.     

An investigation of heavy metal exposure and risks to wildlife in the Kafue flats of Zambia

Exposure and ecological risks to heavy metals (copper, zinc, manganese, iron) at Lochnivar and Blue Lagoon National Parks in wildlife dependent on the Kafue river contaminated with mining waste was evaluated. Samples included water, fish, grasses and Kafue Lechwe (Kobus leche kafuensis) liver. At both parks copper ranged from 0.03-0.04 mg/l; 3.0-6.0 mg/kg; 11.0-44.0 mg/kg; trace -199.0 mg/kg; while zinc was 0.01 mg/l; 32.0-82.0 mg/kg; 15.0-21.0 mg/kg; and 52.0-138.0 mg/kg; in water, fish, grasses and lechwe, respectively. Manganese ranges were 0.15-0.16 mg/l; 7.0-18.0 mg/kg; 51.0-145.0 mg/kg; and 40.0-53.0 mg/kg while iron ranges were 0.13-0.14 mg/l; 26.0-134.0 mg/kg; 1766.0-1797.0 mg/kg; and 131.0-856.0 mg/kg; in water, fish, grasses and lechwe, respectively. Levels in all samples except water were high indicating potential for adverse effects.     

Isolation and molecular characterization of Mycobacterium bovis from Kafue lechwe (Kobus leche kafuensis) from Zambia

Bovine tuberculosis (BTB) is a chronic bacterial disease caused by Mycobacterium bovis. Infections due to M. bovis, which serves as a stable reservoir, can pose serious challenge to control and eradicate in both wildlife and livestock at the interface. This study aimed at isolating and characterizing M. bovis from Kafue lechwe (Kobus leche kafuensis) and black lechwe (Kobus leche smithemani) at the animal/human interface in Zambia. The samples with lesions compatible with BTB collected during the hunting seasons of 2009 and 2010 were cultured for isolation of mycobacteria using Stonebrink with pyruvate (BD Diagnostics, MD, USA) and Middlebrook 7H10 (BD Diagnostics) slants. Isolated mycobacteria were identified using IS6110 polymerase chain reaction and deletion analysis. Molecular characterization of the isolates was performed using spoligotyping and mycobacteria interspersed repetitive unit–variable number tandem repeat (MIRU–VNTR) with nine loci. Data was analyzed using BioNumerics software 6.1. Out of the 39 samples, acid fast bacilli were detected in 27 (69.2 %) based on smear microscopy. Seven isolates were found to belong to Mycobacterium tuberculosis complex, and all were identified as M. bovis based on deletion analysis. All seven isolates were identical on spoligotyping as belonging to the SB0120 (SIT 482). MIRU–VNTR differentiated the isolates into five different patterns. This study has confirmed that M. bovis circulates in the Kafue lechwe, and non-tuberculous mycobacteria were detected in the black lechwe in Zambia which represents a wildlife reservoir, with a potential to spillover to cattle and humans. Isolates of M. bovis from lechwe antelopes are much conserved as only one spoligotype was detected. The study has shown that three loci differentiated fairly well. This option is cheap and less laborious, and hence a better option in resource-strained country like Zambia. The study further showed that some of the loci recommended by the European Reference Laboratory are not suitable for typing M. bovis in Zambia.     

Seasonal pattern of bovine amphistomosis in traditionally reared cattle in the Kafue and Zambezi catchment areas of Zambia

Seasonality of bovine amphistomosis in the Southern province of Zambia was established after examining 268 faecal samples from cattle presented for slaughter at Turnpike slaughter slab, Mazabuka. Amphistomosis was found present throughout the year but the highest abundance rate was found during the post-rainy season (47.8%) and the lowest during the cold dry season (24.8%). In the rainy and post-rainy seasons, higher mean egg counts and cattle found positive were recorded than in any other season. The distribution of amphistome eggs was significantly different (p < 0.001) among the four seasons, with the rainy season having higher median egg counts than others. There were no significant differences in abundance rates between sexes or between ages of cattle. A similar seasonality to that of fasciolosis exists and may help in strategic management of Fasciola and amphistomes.     

Pesticide/herbicide pollutants in the Kafue River and a preliminary investigation into their biological effect through catalase levels in fish

The study determined the types of pesticide/herbicide pollutants in water, sediment and fish from the Kafue River. A preliminary investigation of the oxidative stress from these pesticides/herbicides was also assessed by measurement of catalase activity. Water, sediment and fish samples were collected upstream, midstream and downstream the Kafue river in Chingola, Kitwe, Kafue National Park and Kafue Town. Water, sediment and fish muscle were sampled and analysed for pesticides using Gas chromatography. For catalase activity fish liver samples only were examined. The pesticides/herbicides detected in all samples collectively included: Heptachlor, pp'-DDE, Cypermethrin, Chlordane, Toxaphene, Terbufos, Kelthane, Endosulfan, Dieldrin, pp'-DDD, pp'-DDT, Atrazine, Disulfoton, d-trans-Allethrin and Endrin. On the other hand, catalase activity was detected in all fish liver samples from all sites. Its levels increased significantly from Chingola upstream to sites downstream with highest being in Kafue town. This study therefore, demonstrates that there is widespread contamination of the Kafue River with pesticides/ herbicides. It also demonstrates that organochlorides are found throughout the river especially in fish samples. The spectrum of pesticides/herbicides was much wider in fish probably due to bioaccumulation. It was also observed that fish are subjected to oxidative stress as determined by catalase levels. The stress is more pronounced downstream where the catalase levels were significantly higher than Chingola. The observation that more pesticide varieties are also found downstream may suggest a likely causative effect of the pesticides on oxidative stress although this needs further investigation. This study further tentatively highlights the potential dangers of these agro-related substances to dependants of the Kafue River water body and the need to carry out risk assessments and thereafter institute corrective measures to help reduce contamination and adverse effects.     

Risk factors associated with bovine tuberculosis in traditional cattle of the livestock/wildlife interface areas in the Kafue basin of Zambia

We conducted a cross-sectional study from August 2003 to February 2004 to identify risk factors for bovine tuberculosis (BTB) in the Kafue basin of Zambia. We investigated a total of 106 herds of cattle for presence of BTB using the comparative intradermal tuberculin test (CITT) while an interviewer-administered questionnaire was used to gather epidemiological data on herd structure, management and grazing strategies. BTB prevalence at herd level was estimated and possible risk factors were investigated using the multiple logistic regression model. The true herd level prevalence of BTB was estimated at 49.8% (95% CI: 37.9, 61.7%). The logistic regression model showed that cattle herd BTB status was highly associated with area and husbandry practices. When compared to Kazungula, cattle herds in Blue Lagoon were more likely to test positive for BTB when other factors such as management practices were controlled (OR=10.5). In terms of grazing strategies, transhumant herds (TH) had higher odds (OR=3.0) of being positive compared to sedentary herds (OR=1.0). The results in this study provide preliminary information about potential risk factors that were found to be associated with BTB status in cattle.     

Brucella seroprevalence of the Kafue lechwe (Kobus leche kafuensis) and Black lechwe (Kobus leche smithemani): exposure associated to contact with cattle

We investigated Brucella seroprevalence in Kafue (Kobus leche kafuensis) and Black (Kobus leche smithemani) lechwe antelopes to assess Brucella infections in relation to presence/absence of cattle interaction on the wetlands. Accordingly, two study populations based on cattle interaction were assesed: Kafue lechwe from Kafue flats which interact with cattle; and the Black lechwe with no known interaction with cattle from the Bangweulu swamps. Fourteen Kafue lechwe and thirty Black lechwe were slaughtered between October and December 2009 using special research licenses obtained from the Zambia wildlife authority to investigate diseases in lechwe antelope. For the purpose of this study, blood was collected and sera separated for Rose Bengal and indirect ELISA tests. Seroprevalence of Brucella in the Kafue lechwe was estimated at 42.9% [95% CI: 15.2-70.5] while that in Black lechwe was 0% [95% CI:0.0-11.6]. On the Kafue flats, cattle were spotted grazing in the same areas as lechwe while there was no evidence of cattle presence on the Bangweulu swamps. These differences in seroprevalence between Kafue lechwe and Black lechwe were assumed to be associated with interaction between Kafue lechwe and Brucella infected cattle, and no such contact existed between cattle and the Black lechwe. Our study suggests that brucellosis in the Kafue lechwe may have originated from cattle but has now established a reservoir in wild animals. It is also important to keep in mind that the Black lechwe can easily become infected with Brucella spp. once cattle are introduced in the surrounding areas.     

Hepatic and renal concentrations of copper and other trace elements in hippopotami (Hippopotamus amphibius L) living in and adjacent to the Kafue and Luangwa Rivers in Zambia

Hepatic and renal concentrations of the elements arsenic, cadmium, cobalt, copper, lead, manganese, mercury, molybdenum, selenium and zinc were studied in samples collected from hippopotami from the Kafue River in the Kafue National Park and the Luangwa River in the Southern Luangwa National Park in Zambia. There were no significant differences between trace element concentrations in the tissues of the hippopotami taken in the Kafue River and the Luangwa River. The concentrations of copper and other essential elements were similar to those reported in normal domestic and wild ruminants. Judging by the results obtained in this study, pollution from the mining activity around the Kafue River drainage area in the Copperbelt region has not led to any accumulation of elements in tissues of the hippopotami in the Kafue National Park. The trace element concentrations observed may serve as reference for similar future studies on hippopotami.