Impact of dogs with deltamethrin-impregnated collars on prevalence of visceral leishmaniasis

Road-map of pre-clinical treatment for Visceral Leishmaniasis

Visceral leishmaniasis (VL) or Kala-azar, is the most lethal form of leishmaniasis, is still prevalent in many countries where it is endemic. It is a threat to human life caused by protozoan parasite Leishmania donovani. The severity of the disease is further increased as the treated individuals might have a chance of developing Post Kala-azar Dermal Leishmaniasis (PKDL) in the long run. Moreover, several countries have reported high number of HIV-VL co-infected patients. Therefore, there is a dire need for the development of efficient diagnostic methods and drugs in order to combat the disease and to control the spread of disease. At present, the treatment for VL entirely relies on therapeutic drugs as no vaccine is available yet. Ever since 1900s a series of drugs have been invented and used for treatment of VL; but the need for one such cost-effective treatment that would completely cure the disease with minimal side-effects, low relapse rate with high efficacy and less toxicity remains yet to be fulfilled. Therefore, identifying novel compounds is very crucial to develop potent antileishmanial agents. Thus, this review enlists several instances of drug development, including the pharmacokinetic and pharmacodynamic properties of antileishmanial drugs, different experimental animal models used to investigate the disease progression and to analyze treatment dosage and pharmacological aspect of drugs. Furthermore, the existing gap in drug development and future measures to improve the process are also discussed in this review.

Impact of cattle on joint dynamics and disease burden of Japanese encephalitis and leptospirosis

Japanese encephalitis (JE) is a mosquito-borne neglected tropical disease. JE is mostly found in rural areas where people usually keep cattle at home for their needs. Cattle in households reduce JE virus infections since they distract vectors and act as a dead-end host for the virus. However, the presence of cattle introduces risk of leptospirosis infections in humans. Leptospirosis is a bacterial disease that spreads through direct or indirect contact of urine of the infected cattle. Thus, cattle have both positive and negative impacts on human disease burden. This study uses a mathematical model to study the joint dynamics of these two diseases in the presence of cattle and to identify the net impact of cattle on the annual disease burden in JE-prevalent areas. Analysis indicates that the presence of cattle helps to reduce the overall disease burden in JE-prevalent areas. However, this reduction is dominated by the vector's feeding pattern. To the best of our knowledge, this is the first study to examine the joint dynamics of JE and leptospirosis.

Modelling Sand Fly Lutzomyia longipalpis Attraction to Host Odour: Synthetic Sex-Aggregation Pheromone Dominates the Response

Zoontic visceral leishmaniasis (ZVL) due to Leishmania infantum is a potentially fatal protozoan parasitic disease of humans and dogs. In the Americas, dogs are the reservoir and the sand fly, Lutzomyia longipalpis, the principal vector. A synthetic version of the male sand fly produced sex-aggregation pheromone attracts both female and male conspecifics to co-located insecticide, reducing both reservoir infection and vector abundance. However the effect of the synthetic pheromone on the vector’s “choice“ of host (human, animal reservoir, or dead-end host) for blood feeding in the presence of the pheromone is less well understood. In this study, we developed a modelling framework to allow us to predict the relative attractiveness of the synthetic pheromone and potential alterations in host choice. Our analysis indicates that the synthetic pheromone can attract 53% (95% CIs: 39%–86%) of host-seeking female Lu. longipalpis and thus it out-competes competing host odours. Importantly, the results suggest that the synthetic pheromone can lure vectors away from humans and dogs, such that when co-located with insecticide, it provides protection against transmission leading to human and canine ZVL.