Abstract
Visceral Leishmaniasis is a deadly disease caused by Leishmania infantum, endemic in more than 98 countries across the globe. Although the most common means of transmission is via a sand fly vector, there is growing evidence that vertical transmission may be critical for maintaining L. infantum infection within the reservoir, canine, population. Vertical transmission is also an important cause of infant morbidity and mortality particularly in sub-Saharan Africa. While vertical transmission of visceralizing species of Leishmania has been reported around the globe, risk factors associated with this unique means of Leishmania transmission have not been identified therefore interventions regarding this means of transmission have been virtually non-existent. Furthermore, the basic reproductive number, (R0), or number of new L. infantum infections that one infected mother or dam can cause has not been established for vertical transmission, also hampering the ability to assess the impact of this means of transmission within reservoir of human hosts. Canine Leishmaniosis (CanL) is enzootic within a U.S. hunting dog population. CanL is transmitted within this population via transplacental transmission with no reported vector transmission, despite many repeated attempts to find infected sand flies associated with these dogs and kennels. This population with predominantly, if not solely, vertical transmission of L. infantum was used to evaluate the critical risk factors for vertical transmission of Leishmania and establish the R0 of vertical L. infantum infection. Evaluation of 124 animals born to eighteen dams diagnostically positive for infection with L. infantum showed that there was a 13.84x greater chance of being positive for L. infantum within their lifetime if the mother was also positive within her lifetime (RR: 13.84, 95% CI: 3.54–54.20, p-value: <0.0001). The basic reproductive number for vertically transmitted L. infantum within this cohort was 4.12. These results underscore that there is a high risk of L. infantum infection to transmit from mother to offspring. Targeted public health interventions and control efforts that address vertical transmission of L. infantum are necessary in endemic countries to eliminate visceral leishmaniasis.
Highlights
Leishmaniosis is a disease caused by the obligate intracellular protozoan parasite Leishmania infantum [1,2,3]
Canine leishmaniosis (CanL) is a deadly disease caused by Leishmania infantum parasite, it is found in animal populations, including people, in more than 98 countries across the globe
We found that within the U.S hunting dog population Canine Leishmaniosis (CanL) is transmitted from mom to pup with no reported sand fly transmission in the population, despite multiple attempts to find infected sand flies associated with these dogs
Summary
Leishmaniosis is a disease caused by the obligate intracellular protozoan parasite Leishmania infantum [1,2,3]. Zoonotic visceral leishmaniasis (ZVL) occurs in countries where the disease is endemic/enzootic in both human and animal populations. Within these countries the parasite is transmitted primarily via the phlebotomine sand fly [6, 7], the role of other means of transmission, vertical transmission, is not known. Dogs play an important role in the ecology and control of ZVL as they are the predominant domestic reservoir for the disease, with greater than 10% seropositivity often evident in dogs prior to emergent VL observed in people [8]. Dog ownership is a risk factor of human visceral leishmaniasis in multiple endemic countries with ZVL including Iran, Ethiopia, and Brazil [9,10,11]. Dogs remain an important model system for understanding the ecology and epidemiology of VL [12,13,14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
