Evaluation of deltamethrin-impregnated bed nets and curtains for control of zoonotic cutaneous leishmaniasis in a hyperendemic area of Iran.

In the study carried out in the rural district of Borkhar (Isfahan, Iran) from March 2003 to March 2004 efficacy of deltamethrin impregnated bed nets (IBs) and curtains (ICs), polyester mesh size 156 holes/ inch2, (25 holes/cm2) were compared to that of non-impregnated bed nets (NIBs) and curtains (NICs), in relation to zoonotic cutaneous leishmaniasis (ZCL) control. Deltamethrin impregnated bed nets and curtains at 25 mg a.i./m2 were distributed among 168 households in one of the villages and NIBs plus NICs among the same number of households in another village. In the third village similar numbers of households were used as control. Health education messages were disseminated to ensure the population's compliance with the proper use of bed nets and curtains in the two intervention areas. Entomological surveys using sticky paper traps were carried out in ten households in each village for the collection of sand flies from indoors and outdoors, every two weeks to assess the impact of insecticide impregnated bed nets and curtains on the density of Phlebotomus papatasi. Deltamethrin susceptibility tests and also bioassay tests were carried out on this species by WHO standard method. Case findings were done by house-to-house visits once a season and all the inhabitants of the selected households in each village were examined. The results showed that IBs and ICs can provide a definite personal protection against sand fly bites and interrupted the transmission of ZCL in the intervention village. NIBs and NICs did not provide any protection against the disease. There was no significant difference in monthly density of P. papatasi in indoors and outdoors among the villages (P > 0.05). Susceptibility tests showed that this species was susceptible to deltamethrin in the field population in the area. Bioassays confirmed that the treated nets with deltamethrin remain effective for more than three months and was an excellent mean of individual protection. It is recommended that IBs and ICs can be used widely in the control of ZCL in other similar foci such as hyperendemic and mesoendemic areas of Iran.

Field trial for the control of zoonotic cutaneous leishmaniosis in Badrood, Iran.

BACKGROUND: Due to the resurgence of zoonotic cutaneous leishmaniosis (ZCL) in some nonendemic areas of Iran, extensive studies have been conducted on the epidemiology of the disease in different parts of the country in recent years. The objective of this study was to determine the effects of rodent control on the reduction of the incidence of ZCL in an endemic area in Badrood, Iran. PATIENTS AND METHODS: A survey was carried out in a circle around two villages between April 1997 and January 1999. The control strategy adopted in 1997 consisted of the destruction of the colonies of gerbilline rodents by digging in a radius of 500 m from houses in the intervention area. Opened burrows were baited with zinc phosphide. One village was used as control. Evaluation was made in 1998 and no other control measures were carried out in the area. Case findings were done by house-to-house visits once every season during 1997 and 1998, and all the inhabitants of the selected villages were examined. RESULTS: The average reduction of rodent holes was calculated at 87.4% one year after the first baiting in the intervention area. Changes in the number of rodent holes and the incidence of the disease in the intervention and control villages were statistically significant (P-value <0.000001). CONCLUSION: Our evaluation demonstrated that the control program reduced the incidence of ZCL 12-fold in the treated village compared to the control at the end of the first year of operation, and to more than one-fifth of its original level after two years. The results show that the field control method is very effective in destroying rodents and reducing the incidence of ZCL on a small scale and in special circumstances.