Effect of Farm Additives on the Potential Bioavailability of Some Nutritional Elements from Kenyan Wild Plants.

In this study, the effects of farm additives on eight wild plants from Nyamira County, Kenya were evaluated for their release of iron, copper, calcium, potassium and magnesium. A hundred and sixty traditional medicinal practitioners were surveyed and found to use Solanum indicum, Carissa edulis, Urtica dioica, Clerodendrum myricoides, Aloe vera, Plectranthus barbatus, Bidens pilosa and Solanum mauense. Atomic absorption spectrophotometer was used to determine the total nutritional element contents in the plants while ultra filtration and physiologically based extraction tests were used to determine the release and solubility of the nutritional elements. The plants from areas with high use of farm additives were found to have statistically significant high total levels of copper from the area with no or little application. Elemental analysis of the molecular species fractions into < 3 kDa, 3-10 kDa, 10 kDa-0.45 µm and 0.45-5 µm mass fractions showed that the mass distribution of the elements in the plants depended on the element. The nutritional elements released by gastrointestinal digestion were more than those released aquatically. Farm additives had no significant effect on the levels of most nutritional elements determined and the plants can be used as mineral element supplements in the human body in addition to their therapeutic activity.

Comparison of aqueous and enzymatic extraction combination with sequential filtration for the profiling of selected trace elements in medicinal plants from Kenya.

This work presents results for the profiling of eight essential elements (Co, Cu, Ni, V, Mo, Mn, Zn and Cr) in aqueous and enzymatic extracts of eight anti-diabetic medicinal plants, used by Traditional Medicine Practitioners from Nyamira County, Kenya determined by ICP-MS. The plants used in the study were Solanum indicum, Plectranthus barbatus, Ultrica dioica, Bidens pilosa, Solanum mauense, Clerodendrum myricoides, Carissa edulis and Aloe vera. A sequential filtration procedure was applied to fractionate the elemental contents of the obtained aqueous extracts into molecular size fractions. The results indicate that the low molecular size species (<3 kDa) were predominant for Mo, Zn, Ni, Co, Mn and Cu, while the moderately large species (10 kDa-0.45 µm) of V were predominant in most of the medicinal plant extracts. In addition enzymatic extraction was compared to aqueous extraction to study the effect of the gastric and intestinal conditions on the release of selected elements from the plants. The amount of the elements extracted by the gastric phase enzymes was higher than the amount extracted by the intestinal phase enzymes. In general, the determined elemental amounts of enzymatic extractions were higher than those of corresponding water extractions for 70% of the elements studied.

Sequential Extraction as Novel Approach to Compare 12 Medicinal Plants From Kenya Regarding Their Potential to Release Chromium, Manganese, Copper, and Zinc.

This study is focusing on a novel approach to screen a large number of medicinal plants from Kenya regarding their contents and availability of selected metals potentially relevant for treatment of diabetes patients. For this purpose, total levels of zinc, chromium, manganese, and copper were determined by flame atomic absorption spectrometry and inductively coupled plasma mass spectrometry as well as BCR sequential extraction to fractionate the elemental species in anti-diabetic medicinal plants collected from five natural locations in two sub counties in Nyamira County, Kenya. Solanum mauense had the highest zinc level of 123.0 ± 3.1 mg/kg while Warburgia ugandensis had the lowest level of 13.9 ± 0.4 mg/kg. The highest level of copper was in Bidens pilosa (29.0 ± 0.6 mg/kg) while the lowest was in Aloe vera (3.0 ± 0.1 mg/kg). Croton macrostachyus had the highest manganese level of 1630 ± 40 mg/kg while Clerodendrum myricoides had the lowest (80.2 ± 1.2 mg/kg). The highest level of chromium was in Solanum mauense (3.20 ± 0.06 mg/kg) while the lowest (0.04 ± 0.01 mg/kg) were in Clerodendrum myricoides and Warburgia ugandesis among the medicinal plants from Nyamira and Borabu, respectively. The levels of the elements were statistically different from that of other elements while the level of a given element was not statistically different in the medicinal plants from the different sub counties. Sequential extraction was performed to determine the solubility and thus estimate the bioavailability of the four investigated essential and potentially therapeutically relevant metals. The results showed that the easily bioavailable fraction (EBF) of chromium, manganese, zinc, and copper ranged from 6.7 to 13.8%, 4.1 to 10%, 2.4 to 10.2%, and 3.2 to 12.0% while the potentially bioavailable fraction (PBF) ranged from 50.1 to 67.6%, 32.2 to 48.7%, 23.0 to 41.1%, and 34.6 to 53.1%, respectively. Bidens pilosa, Croton macrostachyus, Ultrica dioica, and Solanum mauense medicinal plants used to treat diabetes by 80 % of the herbalists in Nyamira County were found to be rich in chromium, manganese, copper, and zinc. The EBF of zinc, manganese, and chromium constitutes adequate amounts recommended for daily intake not exceeding the ADI and delivered a low percentage of RDA when estimating daily intake during therapy from typically applied doses. The plants did not show any significant differences at p < 0.05 in terms of concentrations of the elements between the two study areas though the levels of the different elements were statistically significant. Another major observation was that high total levels of the metals in a given plant did not necessarily translate to high bioavailable levels, and hence the need to determine bioavailable form as it is the one accessible to the patient.

Comparison of indirect fluorescent antibody test and enzyme linked immunosorbent assay in the detection of exposure of cattle to Theileria parva in Kenya.

Appraisal of the indirect fluorescent antibody test (IFAT) and antigen enzyme linked immunosorbent assay (ELISA) serological tests as carried out to detect cattle exposed to Theileria parva at the National Veterinary Research Centre, Muguga (NVRC), Kenya is reported. Using sera from T. parva naive cattle and cattle experimentally exposed to T. parva, the two tests were appraised in terms of their sensitivity and specificity. IFAT and ELISA had the same sensitivity of 90% while ELISA had a higher specificity (90%) than IFAT (80%). A comparison was also made of the capability of the two tests to detect exposure of dairy cattle to T. parva prior to immunization against East Coast fever (ECF). The positive outcome from the IFAT was significantly higher (chi 2 = 30.36; P < 0.001) than that from the ELISA. The agreement between the two tests was low (Kappa = 0.21). The two tests indicated a higher risk of ECF in the study area than was expected. Indications are that the ELISA has been effectively adopted at NVRC.

Cost analysis of immunisation against east coast fever on smallholder dairy farms in Kenya.

A spreadsheet model was developed and used to estimate the total cost of immunising cattle against East Coast fever (ECF) based on the infection-and-treatment method. Using data from an immunisation trial carried out on 102 calves and yearlings on 64 farms in the Githunguri division, Kiambu district, Kenya, a reference base scenario of a mean herd of five animals, a 10% rate of reaction to immunisation and a 2-day interval monitoring regimen (a total of 10 farm visits) was simulated. Under these conditions, the mean cost of immunisation per animal was US$16.48 (Ksh 955.78); this was equivalent to US$82.39 (Ksh 4778.90) per five-animal farm. A commonly reported reactor rate of 3% would decrease the cost of US$14.63 (Ksh 848.29) per animal. Reducing the number of farm monitoring visits from 10 to 7 would reduce the total cost by 10%, justified if farmers are trained to undertake some of the monitoring work. The fixed costs were 53% of the total cost of immunisation per farm. The cost of immunisation decreased with increasing number of animals per farm, showing economies of scale.

Pharmaceutical quality of anthelmintics sold in Kenya.

Nine anthelmintic products in pharmacies and from agricultural merchants in Kenya were tested for pharmaceutical quality. The concentration of active drug was compared with the claim on the label, and the variability of several products was tested between batches and between bottles within the same batch. All the products purchased claimed to contain levamisole but its mean (sd) concentration varied from 0 to 118.0 (13.3) per cent of the claimed. The concentration of levamisole in different batches of the same product ranged from 0 to 85.4 per cent of that claimed. One product consisting in part of mebendazole was found to contain 73.2 (9.4) per cent of the claimed concentration of this active component and two products consisting in part of oxyclozanide were found to contain 106.0 (14.4) and 120.6 (6.1) per cent of the expected concentration of oxyclozanide.

Isolation of the causative agent of heartwater (Cowdria ruminantium) from three Amblyomma species in eight Districts of Kenya.

Thirteen isolates of Cowdria ruminantium were made from eight different Districts of Kenya by four different isolation methods. Feeding adult Amblyomma species ticks derived from nymphs collected in the field and the inoculation of homogenates prepared from adult field ticks had the highest success rate. The reattachment of adult ticks collected in the field was successful on only one of five attempts, and the subinoculation of blood from suspected heartwater carriers was unsuccessful. Seven of the isolates were derived from A variegatum ticks, four from A gemma, one from A lepidum and one from a mixed pool of the last two species. This is the first report of the isolation of C ruminantium from A gemma ticks, and the first report of its transtadial transmission from nymphal to adult A gemma.

Effect of interfering ions on hexamethyldisiloxane microdiffusion method.

Acid diffusion in the presence of hexamethyldisiloxane (HMDS) enables complete recovery of ionic fluoride from standards containing varying concentrations of aluminium as one of the main interfering ions. Acid diffusion without HMDS shows a decrease in fluoride recovery as aluminium ion concentration increases. The fluoride concentration in the trapping solution is determined directly on the diffusion cover with a combination fluoride electrode after neutralising and buffering. The same procedure was used for the analysis of fluoride in soil and plant materials containing high concentrations of aluminium ions. For the same samples, the concentrations of aluminium, iron and silicon were determined using atomic absorption spectrophotometer (AAS).

A mild Theileria parva parasite with potential for immunisation against East Coast fever.

Twenty-three Friesian cattle were inoculated subcutaneously anterior to the left prescapular lymph node with 1 ml of a mild isolate of Theileria parva. The cattle developed low macroschizont parasitosis but no clinical reaction was observed. Thirty-five days later the cattle were grouped into five groups and challenged with five different Theileria parva isolates (four cattle-derived Theileria and one buffalo-derived Theileria). The cattle were all solidly immune to challenge with the cattle-derived Theileria isolates but three out of five of the cattle challenged with the buffalo-derived parasite died of theileriosis. All ten non-immunised control cattle developed severe theileriosis and were treated with buparvaquone (Butalex; Pitman-Moore).

Comparison of two microdiffusion methods used to measure ionizable fluoride in cows' milk.

Two microdiffusion methods for measuring ionizable fluoride in cows' milk have been compared. The comparison includes diffusion time, amount of fluoride in spiked and unspiked milk samples and the effect of aluminium as an interfering ion. This work uses an acid diffusion technique involving hexamethyldisiloxane at room temperature and acid diffusion at 60 degrees C in the oven for 20 h. A significant difference was found in diffusion time and in the effect of aluminium ions. There was no significant difference in the amount of fluoride found in the milk samples using the two microdiffusion methods.

Assessing the economic impact of immunisation against East Coast fever: a case study in coast province, Kenya.

The cost of immunising cattle against East Coast fever by the infection and treatment method has been calculated for a pilot scheme in Kaloleni Division of the Coast Province of Kenya by using a spreadsheet model. The cost was calculated to be KSh 544 (US$25) per animal (in 1990 values). If a farmer were to bear all this cost, immunisation would be financially profitable in grade cattle, but the benefits of immunisation would not be sufficient to justify the immunisation of zebu cattle. For these animals, the cost of immunisation would have to be in the range of KSh 230 to KSh 415 per animal, or the farm-gate price of milk would have to increase by at least 80 per cent from KSh 7.50 to 13.50/litre, or the government would have to subsidise the cost either partially or fully. The first two possibilities are realistic, because the costs of routine immunisation are likely to be lower than for the pilot scheme, and because the increasing demand for milk is likely to push up prices in the liberalised markets. If both the grade and zebu cattle in Kaloleni Division were targets for immunisation, it is estimated that there would be 14,500 head for immunisation annually, costing an estimated KSh 8 million. The spreadsheet model used to assess the economics of immunisation in the Kaloleni Division could be applied to determine the government or private veterinary service charges for immunisation that would be financially profitable to farmers in a defined cattle production system in any division, district or country. The model could also be used to estimate the annual total number of cattle for immunisation in a target cattle production system and thus help with the financial planning for the exercise.

Theileria parva carrier state in naturally infected and artificially immunised cattle.

Rhipicephalus appendiculatus adult ticks, collected in the field from zebu (Bos indicus) and exotic (Bos tarus) cattle with high antibody titres to Theileria parva schizont antigen, transmitted Theileria parva infection typical of East Coast fever to susceptible cattle. Uninfected R. appendiculatus nymphs applied to naturally recovered zebu and exotic cattle kept under tick-free conditions in the laboratory for 16 and 7 months respectively, transmitted fatal theileriosis to susceptible cattle. Cattle immunised by the infection and treatment method were shown to be carriers of Theileria parva by examination of the salivary glands of ticks applied to them and by tick transmission. Three and 7 months after immunisation, Theileria parva infected lymphocytes were established in vitro from peripheral blood lymphocytes. This was the first demonstration, in vitro, of the existence of schizonts in Theileria parva (East Coast fever) infection carrier status. These studies show that cattle from endemic and epidemic areas of East Coast fever (ECF) become carriers thereby maintaining the T. parva population. The relevance of the findings in this study to the control of ECF by dipping, immunisation and treatment is discussed.

Generalised demodicosis in a Friesian heifer from a zero-grazing unit.

A Friesian heifer with generalised skin lesions was slaughtered after unsuccessful treatment. It had thickened skin with lumps and nodules, with the severely affected parts thrown into folds over the eyelids, ears, most of the head, neck, legs and perineal area. The affected skin was soft and squamous in appearance. On postmortem examination, all the skin layers were affected and were 10-22 mm thick. There was also lymphadenopathy. Histological examination showed the presence of dermatitis characterised by follicular inflammation. Multiple follicular cysts with keratin squames and numerous demodectic mites were seen. Some mites had migrated to the peripheral lymph nodes causing eosinophilic lymphadenitis and panniculitis of the subcutis.

Response of falciparum malaria to chloroquine and three second line antimalarial drugs in a Kenyan coastal school age population.

Ambulatory rural school children in the Mombasa area with P. falciparum parasitaemia were examined and randomly assigned to treatment with one of three second-line antimalarials--amodiaquine, pyrimethamine/sulphadoxine (P/SD) and pyrimethamine/sulfalene (P/SL). Clinical signs and parasitaemia were followed daily for the first week and on days 14 and 28. WHO Mark II schizont inhibition tests were performed for all the above 3 drugs and chloroquine. The total number of cases was 73. The mean parasite density was 142.1 +/- 207; 102.7 +/- 166; 82.74 +/- 93 parasites per 300 WBC for amodiaquine, P/SD, and P/SL, respectively. In vitro tests showed a chloroquine resistance rate of 60% and no resistance to all of the second line drugs. Also, all children treated successfully cleared their parasitaemia with mean clearance rates of 2.05 +/- 0.57; 1.86 +/- 0.47; 2.05 +/- 0.50 days for amodiaquine, P/SD and P/SL, respectively. Even though, no difference in the effectiveness between the second line drugs used was found, reinfection rates as depicted by day 28 parasitaemia differed--amodiaquine 16%; P/SD 0%; and P/SL4.35%. This difference could be attributed to the difference in the pharmacokinetic properties of the drugs.

PIP: In Kenya, in May-June 1990, clinicians screened 728 primary school children in Mazeras, a coastal village, for Plasmodium falciparum parasitemia and randomly assigned them to receive 1 of 3 second-line antimalarials (amodiaquine, pyrimethamine/sulfadoxine [P/SD], and pyrimethamine/sulfalene [P/SL] to treat malaria. Laboratory personnel at the Coast Provincial General Hospital conducted WHO Mark II schizont inhibition tests for all 3 antimalarials and chloroquine. The clinicians followed the children every day for the first week and at 2 and 4 weeks. 10.44% (76) of the children had falciparum malaria (=or 40 asexual parasites/300 WBC). 3 were lost to follow-up, so 73 children were part of the in vivo study. Prior to treatment, mean parasite densities were 142.1/300 WBC for the amodiaquine group, 102.7/300 WBC for the P/SD group, and 82.74/300 WBC for the P/SL group. The mean clearance time for 2.05 days for amodiaquine, 1.86 days for P/SD, and 2.05 days for P/SL. By day 14, none of the children had parasitemia and no differences in mean body temperatures existed. On day 28, 16% of the children in the amodiaquine group and 4.35% of those in the P/SL group were reinfected compared to none in the P/SD group (p .05). Differences in the pharmacokinetic properties of these second line antimalarials may account for the difference in reinfection rates. 60% of the isolates were resistant to chloroquine. None were resistant to the second line drugs. Isolates were highly sensitive to both P/SD and P/SL. These findings show the need for the Kenyan Ministry of Health to reexamine chloroquine as a treatment for falciparum malaria in areas of confirmed high chloroquine resistance.

Trial of the efficacy and immunological response to an inactivated mycoplasma F38 vaccine.

Goats on two zero grazed farms carrying 1621 animals with a history of contagious caprine pleuropneumonia were subjected to a vaccine trial with an inactivated mycoplasma F38 vaccine. The results indicated that the vaccine produced an immune response, that it was very effective in reducing morbidity and mortality rates, and that a booster dose one month after the first dose of vaccine gave extra protection.

Observations on rinderpest in Kenya, 1986-1989.

Rinderpest was confirmed in Kenya in 1986, 1987, 1988 and 1989. Three epidemiologically distinct events appear to have occurred: repeated outbreaks in West Pokot district related to cross-border movement of stock, an outbreak in Marsabit district in 1987 (thought to have been caused by illegal movement of cattle, possibly in vehicles, from countries further north) and a series of related outbreaks in and near Nairobi between 1988 and 1989 due to the unauthorized movement from abattoirs and holding grounds of slaughter stock possibly introduced from West Pokot or Marsabit. In West Pokot the disease affected unvaccinated calves and yearlings. In Marsabit cattle of all ages were affected. In August 1988, a major outbreak was confirmed in Kiambu and Kajiado districts in central Kenya, near Nairobi. At the same time a provisional diagnosis of rinderpest was made in a herd of cattle at a slaughterhouse in Nairobi. Rinderpest virus was isolated from sick cattle in all the outbreaks. Experimental infection of susceptible cattle with the Kiambu isolate demonstrated this to be of low virulence. Emergency vaccination and quarantine measures instituted immediately after confirmation eliminated clinical disease within three to four weeks in West Pokot, Kiambu and Nairobi. In Kajiado, however, the disease persisted for at least nine months, during which time a series of virus isolates was recovered. There was no evidence of infection in susceptible wildlife. This increase in the incidence of rinderpest in Kenya in recent years serves to highlight the problems of control and the need for concerted efforts to eradicate the threat of the disease from East Africa.

Further evaluation of the use of buparvaquone in the infection and treatment method of immunizing cattle against Theileria parva derived from African buffalo (Syncerus caffer).

Three experiments were undertaken to determine the efficacy of different doses of buparvaquone in the infection and treatment immunization of cattle against Theileria parva derived from African buffalo (Syncerus caffer). Two of these experiments also compared buparvaquone with standard doses of long- and short-acting formulations of oxytetracycline. In addition, different dilutions of stabilates were used in the experiments. In the first experiment, a 10(-1.0) dilution of stabilate was used to infect groups of cattle treated with buparvaquone at doses of between 5 and 0.625 mg kg-1 body weight (bwt) on Day 0 after infection. All control cattle developed severe theileriosis and none of the treatment regimes (including those utilizing long-acting oxytetracycline) prevented the development of theileriosis. Treatment with buparvaquone at 2.5 mg kg-1 bwt or oxytetracycline gave the most satisfactory results. In the second experiment when the sporozoite dose was reduced to 10(-2.0) dilution, buparvaquone treatment at 5 and 2.5 mg kg-1 bwt and short- and long-acting formulations of oxytetracycline reduced reactions greatly. While all the oxytetracycline treated animals produced a serological response and were immune to a 50-fold higher challenge with the immunizing stabilate, several animals in the buparvaquone groups did not show a serological response and were not immune to challenge. In the third experiment, groups of cattle were infected with 10(-1.2), 10(-1.4) and 10(-1.6) dilutions of stabilate and were treated with 2.5 mg kg-1 bwt of buparvaquone. No animals developed severe theileriosis and all seroconverted. On homologous challenge, however, two out of 14 cattle showed severe reactions. It was concluded that further work on immunization using buparvaquone treatment at 2.5 mg kg-1 bwt and 10(-1.6) dilution of the stabilate would have to be carried out before such a system could be used in the field.

Immunisation of cattle against theileriosis in Nakuru District of Kenya by infection and treatment and the introduction of unconventional tick control.

One hundred and one cross European-Boran cattle (50 cows and 51 calves), on a farm in Nakuru District, Kenya, were immunised against theileriosis using Theileria parva lawrencei and Theileria parva parva stocks from another district of Kenya. The stabilates used were T.p.lawrencei (Mara III) used at 10(-1.7) dilution and T.p.parva (Kilae) used at 10(-1.0) dilution. The stabilates were combined and inoculated simultaneously with a short-acting formulation of oxytetracycline hydrochloride given intramuscularly at 10 mg kg-1 body weight and was repeated on Day 4 after inoculation of the stabilate. Most of the theileriosis challenge on the farm was thought to be derived directly from the African buffalo (Syncerus caffer). Nine percent of the cattle had significant indirect fluorescent antibody (IFA) titres before the immunisation and 99% after immunisation. The immunised cattle were exposed to tick-borne disease challenge on the farm by withdrawal of acaricide cover. The immunised cattle were divided into five groups plus two susceptible control cows and two calves for each group. Cattle in four of the groups had acaricidal ear tags, each group having a different type, applied to both ears and the fifth group remained untagged. The animals remained without conventional acaricide application for 134 days. Ten out of 20 (50%) non-immunised control cattle became T.p.lawrencei reactors which only one out of 97 (1%) of the immunised cattle reacted. A frequent complication noted was mild infections due to unidentified Theileria sp. which required expert differentiation from T.parva infections. An additional group of ten steers whose tick load was removed by hand at weekly intervals was introduced 79 days after exposure; these had no tick control and four became T.p.lawrencei reactors. Of 12 calves born during the exposure period and without tick control, four became theilerial reactors and one died. The application of acaricidal tags however, reduced tick infestation levels considerably compared with untagged controls but did not prevent transmission of theileriosis with the possible exception of tags on Group 4. A number of transient low grade fevers were noted and attributed to Theileria sp., Ehrlichia bovis, Ehrlichia (Cytoecetes) ondiri and Borrelia theileri infections, none of which were fatal. One immunised animal died of acute dual infection of Babesia bigemina and Borrelia theileri after acaricide control by spraying was re-introduced but no Anaplasma infections were detected. An analysis of the economic effects of immunisation was made.