Abstract:
The endosymbionts present in the gut of disease vectors play crucial roles in their physiology and vectorial competence, potentially influencing transmission dynamics. This creates avenues for disease control in vectors by exploring the vector microbiome. Leishmaniasis is a significant neglected tropical disease traditionally known to be transmitted by Phlebotomine sandflies. The cutaneous form of the disease caused by the new species Leishmania chancei of the Leishmania (Mundinia) enrietii subgenus is endemic in the Volta Region of Ghana, with the vectors responsible for transmission unknown. This study investigated the presence of selected endosymbionts in the guts of potential vectors and their anticipated potential roles in the development of Leishmania parasites which may consequently influence disease transmission and lesion exacerbation. A total of 135 sandflies and 750 biting midges were caught by light traps in leishmaniasis-endemic communities in Ghana. The vectors were subsequently pooled (5 sandflies per group and 10 biting midges per group) and subjected to DNA extraction. Universal and specific 16s bacterial primers were employed to perform PCR screening for Wolbachia, Ochrobactrum, Ehrlichia, and Tsukamurella. Among the 27 pools of sandflies (135 individuals), 18.5% tested positive for Wolbachia, 100% for Ehrlichia, 3.7% for Ochrobactrum and 70% for Tsukamurella. Out of the 75 biting midges pools (750 individuals), 11% tested positive for Wolbachia, 41% for Ehrlichia, 47% for Ochrobactrum and 64% for Tsukamurella. Additionally, we amplified the Leishmania parasite in 55.6% of sandfly pools and 52% of the biting midges pools. Co-infections of Leishmania and bacteria were amplified in 11%, 56%, and 33% of sandflies for Wolbachia, Ehrlichia, and Tsukamurella respectively. Notably, no sandflies showed coinfection with the Leishmania parasite and Ochrobactrum. On the other hand, biting midges exhibited a co-infection rate of 5.3%, 23%, 24%, and 28% for Wolbachia, Ehrlichia, Ochrobactrum and Tsukamurella respectively with the parasite. The presence of Wolbachia, Ehrlichia, Ochrobactrum and Tsukamurella in the potential vectors along with the observed coinfections with the Leishmania parasite suggests possible interactions between these microorganisms within the vector’s gut. These interactions may significantly influence the establishment of infections in vectors and subsequent disease transmission. To gain further insights into the gut microbial community of the potential vectors, sequencing of amplicons should be carried out to uncover the molecular foundations of the intricate relationships between the vectors and their microbiome. This study opens new discourse for investigating the vector microbiome, understanding its role in disease transmission dynamics and how to exploit the microbiome for disease prevention and control.
