6533b861fe1ef96bd12c4e31

RESEARCH PRODUCT

Dogs and Guinea worm eradication

subject

description

After 30 years of control campaigns, guinea worm faces eradication. However, dogs are expected to thwart the eradication of dracunculiasis as they act as alternative hosts of the worm. The health community un doubtedly have to recognise the success of the Guinea Worm Eradication Program (GWEP), although some flaws cannot be overlooked. One of the most essential points when trying to achieve the control of parasitic infections is to determine the role of reservoirs that could maintain the disease. Erroneously, dogs are likely to have been ignored as reservoirs of Dracunculus medinensis so far. I fi nd it hard to believe that a parasite that has always been considered specific to humans is able to adapt perfectly to a supposedly new host in such a short period of time. The considerable increase in the number of infected dogs detected in Chad in 2015 has led to the assertion that there was a “mysterious epidemic” of dracunculiasis in that country. On the contrary, I believe that the reward off ered since February, 2015, (US$20) for reporting infected dogs in Chad has provoked the increase in the detection of parasitised dogs from that month onwards. Before trying to analyse the peculiar epidemiology of dracunculiasis in Chad, experts should consider that these results are likely to be the direct consequence of this incentive in such a poor country, where the monthly minimum wage is around $110. Several other factors should also be considered. First, it seems that the only information available about the presence of guinea worms in dogs came from people living in villages along the Chari River. Apparently, locals cannot recall there being infected dogs in the past. Is that level of reporting reliable enough? Second, dogs, supposedly, become infected by eating the entrails of fi sh with dracunculus larvae. However, these larvae have not been found in any potential paratenic hosts (fi sh, frogs, or lizards). Third, in August, 2014, and 2015, the larvicide temephos was applied to specifi c sections of lagoons where dogs usually drink. This measure was probably taken too late. The infected dogs detected in 2015 probably became infected before the use of the larvicide, considering the long incubation period of D medinensis. These factors notwithstanding, the continued presence of guinea worms in dogs does not mean that the parasite cannot be expected to disappear in humans if they continue to drink safe water.