Field tests were carried out to compare the performance of a new tsetse trap, the Nitse (I and II) with the biconical, F3 and NGU traps respectively at the Yankari Game Reserve, Bauchi State, Nigeria. The game reserve harbours Glossina palpalis, G. tachinoides and G. morsitans submorsitans species. The biconical trap was used as the standard. The sites had been cleared of vegetation; they were 5–10 m away from vehicle paths and about 100 m apart. Each trap was moved rotatingly until all traps were exposed to each of the five sites. Traps were emptied each morning after 24 h and the tsetse sorted according to species and sex. The data on the different trap catches were analysed using the one-way ANOVA and the multiple range test via the SPSS statistical package. The performance of the Nitse I on G. tachinoides in one area with high tsetse density was significantly better than that of each of the three traps. But for G. m. submorsitans, Nitse I and the biconical trap performed better than only the F3 (P ≤ 0.05) in the high density area. Only the biconical performed significantly better than the F3 trap in an area with low tsetse density. The new Nitse trap was more effective for G. tachinoides than for G. m. submorsitans.

The design and construction of the Nitse trap are described. The materials required are: royal blue cotton, black cotton, mosquito netting, brass pipe, metal rods and galvanised wire. The cutting and joining of the various parts to produce the trap and the method of placement are also described. Finally a rough estimate of the cost of the trap is given.

Restriction analysis of total DNAs from Leishmania donovani complex strains revealed heterogeneous distribution of kDNA fragments among the reference strains of L. donovani. The cloned kDNA fragments used as probes in the hybridisation analysis have proven useful for identifying and characterising L. donovani subspecies when screening newly isolated leishmanial parasites from patients, vectors and reservoir hosts. This genetic heterogeneity was confirmed by karyotyping by pulsed field gel electrophoresis of four L. donovani reference strains. A high degree of polymorphism was shown, affecting not only the chromosome size, but also their number.

The pathogenicity of cyclically transmitted C16 clone 1 of Trypanosoma brucei metacyclics which developed within normal and hypertrophied DNA virus-infected salivary glands of Glossina morsitans morsitans was studied in the inbred, BALB/c mice. Microscopic examination of salivary glands obtained from G. m. morsitans with combined virus and T. brucei infections (i.e. the flies which transmitted the trypanosome infection to the test group of mice, group A) revealed that the glands comprised hyperplastic epithelial cells, some of which were fragmented, and numerous metacyclic trypanosomes. All the mice which contracted trypanosomiasis from G. m. morsitans with only T. brucei, i. e., the control mice (Group B; n=4) and the mice in the test group (n = 3) developed high parasitaemia and died. Repeated-measures analysis of variance using adjusted mean rate revealed that the mean prepatent periods and the mean times to death in both the control and the test groups of the BALB/c mice were not significantly different (P > 0.05). Analysis of log-transformed data fitted to a logistic growth model revealed that the rate of multiplication of T. brucei parasites in the blood of the test group BALB/c mice (r=2.373) was greater than in the control mice (r=0.808) and that the maximum carrying capacity was also attained earlier in the former group. These observations imply that the development of T. brucei metacyclics within hypertrophied salivary glands and their co-existence with the DNA virus particles might have enhanced their infectivity and virulence in the mice.