JMM Profile: Bartonella bacilliformis: a forgotten killer

Species identification of phlebotomine sandflies using deep learning and wing interferential pattern (WIP)

Sandflies (Diptera; Psychodidae) are medical and veterinary vectors that transmit diverse parasitic, viral, and bacterial pathogens. Their identification has always been challenging, particularly at the specific and sub-specific levels, because it relies on examining minute and mostly internal structures. Here, to circumvent such limitations, we have evaluated the accuracy and reliability of Wing Interferential Patterns (WIPs) generated on the surface of sandfly wings in conjunction with deep learning (DL) procedures to assign specimens at various taxonomic levels. Our dataset proves that the method can accurately identify sandflies over other dipteran insects at the family, genus, subgenus, and species level with an accuracy higher than 77.0%, regardless of the taxonomic level challenged. This approach does not require inspection of internal organs to address identification, does not rely on identification keys, and can be implemented under field or near-field conditions, showing promise for sandfly pro-active and passive entomological surveys in an era of scarcity in medical entomologists.

Single-nucleotide polymorphisms in ialB, gltA and rpoB genes of Bartonella bacilliformis isolated from patients in endemic Peruvian regions

Bartonella bacilliformis is a Gram-negative, aerobic bacterium and the known causal agent of Carrion's disease, still considered a neglected disease. There is limited information about the nucleotide sequences of this bacterium in international databases, and few studies have addressed the genetic diversity of B. bacilliformis. We analyzed a total of 20 isolates of B. bacilliformis from the Peruvian regions of Ancash and Cajamarca. Three genes (ialB, gltA, and rpoB) were sequenced in each isolate and nucleotide sequences retrieved from GenBank (16 B. bacilliformis genomes) were also included in the study. All this information was merged in order to obtain clearer evidence of the phylogenetic relationships of B. bacilliformis. In the phylogenetic analysis conducted with the concatenated markers, four isolates (B.b-1, B. b-3, B. b- 7, B.b-8) from the Ancash region were observed to form a subgroup different from B. bacilliformis type strain KC583, showing dissimilarity levels of 5.96% (ialB), 3.69% (gltA) and 3.04% (rpoB). Our results suggest that B. bacilliformis consists of two different subgroups. Future investigations are needed to establish the taxonomic status of these subgroups.