A.M. Phiri

Prevalence and distribution of gastrointestinal helminths and their effects on weight gain in free-range chickens in Central Zambia

Examination of helminths from gastrointestinal tracts of 125 free-range chickens in Zambia revealed a 95.2% prevalence rate. The species and their prevalences were: Allodapa suctoria (85.6%), Tetrameres americana (80.8%), Ascaridia galli (28.8%), Gonglonema ingluvicola (50.4%), Raillietina spp. (81.6%) and Heterakis gallinarum (32.8%). No trematodes or Syngamus trachea were found. Mixed infections accounted for 88.2% as compared to 7.2% of single infections. Effects of helminthoses on weight gain were investigated in 100 growing chickens randomly assigned to treatment (levamisole) and untreated control groups. There was a significant mean (±SEM) weight gain (grams) of 812.8 ± 51.4 in the treatment group and 623 ± 57.4 in the control group (p < 0.01). The mean (±SEM) worm burdens from the control group and the treatment group were 96.3 ± 5.61 and 22.05 ± 2.61, respectively. These results confirm the higher risk of helminth infections in free-range systems and may explain the deleterious effects in chickens.

Why Latrines Are Not Used: Communities’ Perceptions and Practices Regarding Latrines in a Taenia solium Endemic Rural Area in Eastern Zambia

Taenia solium cysticercosis is a neglected parasitic zoonosis occurring in many developing countries. Socio-cultural determinants related to its control remain unclear. Studies in Africa have shown that the underuse of sanitary facilities and the widespread occurrence of free-roaming pigs are the major risk factors for porcine cysticercosis. The study objective was to assess the communities’ perceptions, practices and knowledge regarding latrines in a T. solium endemic rural area in Eastern Zambia inhabited by the Nsenga ethno-linguistic group, and to identify possible barriers to their construction and use. A total of 21 focus group discussions on latrine use were organized separately with men, women and children, in seven villages of the Petauke district. The themes covered were related to perceived latrine availability (absence-presence, building obstacles) and perceived latrine use (defecation practices, latrine management, socio-cultural constraints).The findings reveal that latrines were not constructed in every household because of the convenient use of existing latrines in the neighborhood. Latrines were perceived to contribute to good hygiene mainly because they prevent pigs from eating human feces. Men expressed reluctance to abandon the open-air defecation practice mainly because of toilet-associated taboos with in-laws and grown-up children of the opposite gender. When reviewing conceptual frameworks of people’s approach to sanitation, we found that seeking privacy and taboos hindering latrine use and construction were mainly explained in our study area by the fact that the Nsenga observe a traditionally matrilineal descent. These findings indicate that in this local context latrine promotion messages should not only focus on health benefits in general. Since only men were responsible for building latrines and mostly men preferred open defecation, sanitation programs should also be directed to men and address related sanitary taboos in order to be effective.

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.

Trematode infections in freshwater snails and cattle from the Kafue wetlands of Zambia during a period of highest cattle–water contact

A total of 984 snails, comprising nine species, were collected from six areas in the Kafue wetlands between August and October 2003 to assess larval trematode infections. Of these, 135 (13.7%) were positive. Most trematode infections were recorded from Lymnaea natalensis (42.8%), which harboured four of the five morphologically different cercariae found. No trematodes were recovered from Bellamya capillata, Biomphalaria pfeifferi, Melanoides tuberculata, Physa acuta and Cleopatra nswendweensis. One snail (0.2%) of 416 Bulinus snails shed brevifurcate-apharyngeate distome cercariae while three (0.7%) shed amphistomes. Gymnocephalous and longifurcate-pharyngeate distome were the commonest types of cercariae recorded while xiphidiocercaria was the least common. The highest prevalence rates of F. gigantica (68.8%) and amphistomes (50.0%) in cattle (n = 101) were in Chiyasa while those in Kaleya had the lowest (9.1 and 18.2%, respectively). In most habitats, infections were recorded in both cattle and snails. Critical determinants of infection may have been the distance of settlements and/or cattle kraals, the number of animals in nearby homesteads and the presence of susceptible host snails. This study suggests that fascioliasis and amphistomiasis could be major constraints of cattle production in the Kafue wetlands because favourable factors were available to introduce and maintain the infections. It further provides a starting point for some comprehensive studies on snail-related aspects of transmission and snail host ecology in Zambia.

Prevalence of amphistomiasis and its association with Fasciola gigantica infections in Zambian cattle from communal grazing areas.

To estimate prevalence of amphistomiasis and its association with bovine Fasciola gigantica infections in Zambia, 709 faeces of cattle presented for slaughter from three major cattle rearing areas of Central, Southern and Western provinces were analysed. The prevalence rate of amphistomes was 51.6%. Egg counts per gram (EPG) of faeces ranged from 0 to 385 with a mean (+/- SEM) of 11.96 +/- 1.07. The origin of the cattle had a significant influence (P < 0.001) on the prevalence rate. Fasciola gigantica infections accounted for 46.7% of the cattle examined. The mean EPG count (+/- SEM) was 6.3 +/- 0.66 with a range of 0 to 223. A total of 34.6% were mixed infections while single Fasciola and amphistome infections represented 12.1% and 17.1%, respectively. Significantly more cattle (63.8%) were infected with either single or both trematode infections (P < 0.0001) than not. Mixed trematode infections were highest in the Southern province (80.0%) while the lowest were recorded in Central province (16.3%). A positive correlation (r(2) = 0.0428) was present in mixed infections. In order to minimize losses, epidemiology and cross-resistance of amphistomiasis and fascioliasis should be studied in different ecological regions of Zambia to formulate efficient control programmes.

Concurrent infections of Fasciola, Schistosoma and Amphistomum spp. in cattle from Kafue and Zambezi river basins of Zambia

This study investigated interactions among Fasciola gigantica, Schistosoma spp. and Amphistomum spp. concurrent natural infections in Zambian cattle, based on egg and worm counts. In the abattoir 315 cattle were screened for worms of F. gigantica in the liver, Schistosoma spp. in mesenteric veins and/or Amphistomum spp. in the rumen. One hundred and thirty-three (42.2%) of the abattoir-examined cattle harboured one, two or all three trematodes. Of 133 cattle, 50 were randomly selected for worm and egg counts. The mean numbers (+/- SD) of Amphistomum, Schistosoma and Fasciola were 622.08 (+/- 97.87), 33.68 (+/- 7.44) and 19.46 (+/- 4.58), respectively. A total of 32% harboured all the three trematodes, 66% had F. gigantica and Amphistomum spp. infections, 52% had Schistosoma spp. and Amphistomum spp. infections while 32% had F. gigantica and Schistosoma infections. A positive correlation (P = 0.014) was found between F. gigantica and Amphistomum worm burdens. There were no correlations between Amphistomum and Schistosoma worm burdens and between F. gigantica and Schistosoma worm burdens. It may be concluded that there is no significant cross-protection among these trematodes in cattle in endemic areas.

Helminth parasites of the Kafue lechwe antelope (Kobus leche kafuensis): a potential source of infection to domestic animals in the Kafue wetlands of Zambia

The Kafue lechwe antelope (Kobus leche kafuensis), a medium-sized, semi-aquatic antelope, grazes extensively on pastures accessed by livestock in and around Lochinvar and Blue Lagoon national parks in the Kafue wetlands of Zambia. This interaction has a potential for bi-modal transmission of a wide range of parasitic helminths between lechwe and domestic ruminants. A survey was conducted to investigate the status of helminths in the Kafue lechwe during the 2008 (July-December) hunting season, involving 65 animals hunted under special research licences. Worm identification was based on morphological features using standard identification keys. Eleven different types of helminths were identified in the animals studied; namely, Oesophagostomum, Bunostomum, Cooperia, Dictyocaulus, Marshallagia, Stilesia, Setaria, Trichuris, Fasciola, amphistomes and Schistosoma. Amphistomes (100%) and Oesophagostomum (60.9%) were the most common while Fasciola (7.8%) and Stilesia (1.6%) were the least of the identified helminths. There was no evidence that helminths, at intensities observed, adversely affected the health of the lechwe. The degree of worm infection was observed to vary between the two study areas, with Blue Lagoon recording higher infection levels compared to Lochinvar. The host range of many of the helminths found in the Kafue lechwe is broad and could serve as a potentially stable source of infection to domestic animals such as goats and cattle. Therefore, issues concerning livestock management and conservation may arise.

Developing a rapid throughput screen for detection of nematicidal activity of plant cysteine proteinases: the role of Caenorhabditis elegans cystatins

Plant cysteine proteinases (CPs) from papaya (Carica papaya) are capable of killing parasitic nematode worms in vitro and have been shown to possess anthelmintic effects in vivo. The acute damage reported in gastrointestinal parasites has not been found in free-living nematodes such as Caenorhabditis elegans nor among the free-living stages of parasitic nematodes. This apparent difference in susceptibility might be the result of active production of cysteine proteinase inhibitors (such as cystatins) by the free-living stages or species. To test this possibility, a supernatant extract of refined papaya latex (PLS) with known active enzyme content was used. The effect on wild-type (Bristol N2) and cystatin null mutant (cpi-1(-/-) and cpi-2(-/-)) C. elegans was concentration-, temperature- and time-dependent. Cysteine proteinases digested the worm cuticle leading to release of internal structures and consequent death. Both cystatin null mutant strains were highly susceptible to PLS attack irrespective of the temperature and concentration of exposure, whereas wild-type N2 worms were generally resistant but far more susceptible to attack at low temperatures. PLS was able to induce elevated cpi-1 and cpi-2 cystatin expression. We conclude that wild-type C. elegans deploy cystatins CPI-1 and CPI-2 to resist CP attack. The results suggest that the cpi-1 or cpi-2 null mutants (or a double mutant combination of the two) could provide a cheap and effective rapid throughput C. elegans-based assay for screening plant CP extracts for anthelmintic activity.

A comparative study of the efficacy of piperazine and Carica papaya for the control of helminth parasites in village chickens in Zambia.

Village chickens play vital roles in the livelihoods of those people keeping them. Backyard poultry provide a critical source of food and income for people in developing countries (Lans et al. 2007) and so is the case in Zambia. However, their productivity has been hampered by many constraints resulting in low flock sizes (Kusina and Kusina 1999). Among the constraints is the problem of external and internal parasites (Abebe et al. 1997). In Africa, the control of these parasites is limited by the high cost of anthelmintics, their uncertain availability and the increasing frequency of drug resistance (Naidoo et al. 2008). Therefore, possible alternatives such as the use of plant products that function by mechanisms other than those of chemotherapeutics, with the additional advantage of a natural origin have been recommended (Naidoo et al. 2008). Besides, the cost of treatment with alternative traditional methods (herbs) is negligible when compared with the cost of conventional medicines. In addition to being very inexpensive, herbal preparations have good medicinal value (Mbaria et al. 1998). Therefore, in a quest for provision of safe animal products, a number of studies on use of herbal therapy especially in poultry, have been conducted many of which have reported a number of herbal products that are of potential use as therapeutic or prophylactic agents against bacteria (Arshad et al. 2008), protozoa (Nweze and Obiwulu 2009; Naidoo et al. 2008; Arshad et al. 2008) and viruses (Kong et al. 2006). However, only a few herbal products (Lans et al. 2007; Purwati and He 1991) have been reported to be potential antihelmintic agents in poultry. The objective of the current study was to compare the efficacy of Carica papaya latex with that of piperazine in the control of nematode parasites in village chickens as well as assess the effect of treatment on productivity (weight gain). Trop Anim Health Prod DOI 10.1007/s11250-009-9432-6

The Nexus between Bovine Tuberculosis and Fasciolosis Infections in Cattle of the Kafue Basin Ecosystem in Zambia: Implications on Abattoir Surveillance.

Bovine tuberculosis (bTB) and fasciolosis are important but neglected diseases that result in chronic infections in cattle. However, in Zambia, these diseases are mainly diagnosed at abattoirs during routine meat inspection. Albeit the coinfection status, these diseases have been reported as nothing more than normal separate findings without an explanatory phenomena. Forthwith, we formulated this study to assess the possible association of the two diseases in a known high prevalence area on the Kafue basin ecosystem. Of the 1,680 animals screened, 600 (35.7%; 95% CI 33.4%–38%) and 124 (7.4%; 95% CI 6.1%–8.6%) had fasciolosis and tuberculous lesions; respectively, whilst 72 had both fasciola and tuberculous lesions representing 12% (95% CI 9.4%–14.6%) and 58.1% (95% CI; 49.3%–66.7%) of the total positives for fasciola and tuberculosis, respectively. Jaundice was seen in 304 animals, 18.1% (95% CI; 16.3%–19.9%) and was significantly correlated to fasciolosis (r = 0.59, P < 0.0001). A significant association (χ 2 = 76.2, df = 1, and P < 0.0001) was found between fasciolosis and tuberculous lesions. Simple logistic regression intimated fasciolosis as a strong predictor for tuberculous lesions with animals that had fasciola being five times more likely to have tuberculous lesions (odds ratio = 4.8, 95% CI: 3.3–7.0). This study indicates that transmission and spatial risk factors of communicable and noncommunicable diseases such as bTB and fasciolosis can be correlated in an ecosystem such as the Kafue flats.