Assessments of the transmission of Onchocerca volvulus by Simulium sanctipauli in the Upper Denkyira District, Ghana, and the intermittent disappearance of the vector.

Following studies on the transmission of Onchocerca volvulus (Leuckart) by Simulium sanctipauli Vajime & Dunbar (Diptera, Simuliidae) in Upper Denkyira District in Ghana in 2001 and 2002 (Kutin et al., Med Vet Ent 18:167-173, 2004), further assessments were carried out in 2006 and 2013/2014 to determine whether transmission parameters had changed since community-directed ivermectin treatment (CDTI) began in 1999. There were no marked changes of the transmission intensities in 2006. Only slight, but non-significant, reductions were observed in infection rates of parous flies with larval stages (L1-L3) of O. volvulus from 44.1 % (of 1672 parous flies) in 2001/2002 to 42.1 % (506) in 2006 and from 6.5 to 5.9 % of flies carrying infective larvae in their heads. This suggested that there was an ongoing transmission in the area and the parasite reservoir in the human population was still high. Unexpectedly, further assessments conducted in October 2013 and March and October 2014 revealed that the vector S. sanctipauli had apparently disappeared and transmission had ceased, probably as a result of intensified gold mining activities along the rivers Ofin and Pra. The water of both rivers was extremely turbid, heavily loaded with suspended solids, probably preventing the development of blackfly larvae. Some breeding and biting of Simulium yahense Vajime & Dunbar was observed in a small tributary of the Pra, the Okumayemfuo, which is not affected by gold mining. However, the infection rate of flies was low, only 3.7 % of 163 parous flies were infected with first stage (L1) larvae of O. volvulus.

Effects on performance of growing pigs fed diets containing different levels of dried cashew pulp.

The purpose was to investigate the use of dried cashew pulp (DrCP), the sun-dried residue after juice has been extracted from the cashew apple, as a feed ingredient in growing pig diets. The growth rate, feed intake, feed to gain ratio and cost of gain of grower pigs fed diets containing 0 (0DrCP), 100 (100DrCP), 150 (150DrCP) or 200 (200DrCP) g kg(-1) of dried cashew pulp was investigated in a feeding trial set up as a Completely randomized design with 4 treatments replicated 3 times and lasting 112 days. There were no significant differences (P > 0.05) among treatments in the parameters measured. It was concluded that dried cashew pulp could be used in growing pig diets up to a level of 200 g kg(-1) without any deleterious effects. Future work will look at higher levels of DrCP inclusion in the diets of growing pigs.

Evaluation of the filter paper blood collection method for detecting Og4C3 circulating antigen in bancroftian filariasis.

Serological diagnosis of filariasis is generally known to be more reliable than detection of microfilariae. The recently developed Og4C3 enzyme-linked immunosorbent assay (ELISA) for detecting Wuchereria bancrofti circulating antigen has been shown to be very sensitive in diagnosing filiariasis using serum samples. The commercially available form of this ELISA, using whole blood collected on filter paper, has not been validated independently. We evaluated the sensitivity of this new method against standard 20 microL night blood films in 1808 paired samples from 18 communities in different endemic areas of Ghana. The diagnostic performance of the method was consistently low in all but 2 communities (sensitivity = 50.3%). This method of diagnosing filariasis is not suitable for field use in its present form.