Detection of Bartonella spp. in Cimex lectularius by MALDI-TOF MS

Hidden Burden of Bartonella quintana on the African Continent: Should the Bacterial Infection Be Considered a Neglected Tropical Disease?

Bartonella quintana is a louse-borne gram-negative bacillus that remains a poorly characterized cause of bacteremia, fever, and infective endocarditis. Due to the link with pediculosis, B quintana transmission is tied to poverty, conflict, overcrowding, and inadequate water access to maintain personal hygiene. Although these risk factors may be present globally, we argue that a substantial burden of undocumented B quintana infection occurs in Africa due to the high prevalence of these risk factors. Here, we describe the neglected burden of B quintana infection, endocarditis, and vector positivity in Africa and evaluate whether B quintana meets criteria to be considered a neglected tropical disease according to the World Health Organization.

Survey of bed bug infestations in homeless shelters in southern France

Bed bug has become a major public health pest worldwide. Infestation may result in numerous negative health effects. Homeless shelters are one of the most habitats that can be infested with bed bugs, a few studies have focused on bed bug infestations in these settings. We conducted a survey of infestations of bed bugs in a homeless shelter in southern France, using an innovative seven-level scale (0-6) to assess the degree of infestation, MALDI TOF-MS to identify bed bugs, and a biomolecular tool to detect bacteria. Bed bug infestations were documented in 13% (9/68) of investigated rooms. A total of 184 bed bugs were collected and morphologically identified as Cimex lectularius. MALDI TOF-MS analysis allowed us to obtain high-quality MS spectra for all 184 specimens, to correctly identify all specimens, and included 178/184 (97%) Log Score Values higher than 1.8. Among the bacteria tested, Wolbachia sp. DNA was found in 149/184 (81%) of the bed bugs, and one sample was positive for Coxiella burnetii, the agent of Q fever. Our study is the first of its kind that offers new perspectives for increasing public awareness of the conditions in homeless shelters.

MALDI-TOF MS identification of cattle ticks from Cameroon

MALDI-TOF MS has recently been proposed as an accurate tool for arthropod identification, including ticks. In this study, we evaluate and confirm the ability of MALDI-TOF MS, to identify different tick species collected in Cameroon, considering other lines of evidence (morphology and molecular). A total of 1483 adult ticks were collected from cattle in five distinct sites in the Western Highland of Cameroon. Because of engorged status and/or absence of some morphological criteria, some Ixodes spp. and Rhipicephalus spp. were identified to the genus level only. Among those, 944 ticks (543 males and 401 females) were selected for the current work. They were classified into 5 genera and 11 species: Rhipicephalus (Boophilus) microplus (31.7%), Rhipicephalus lunulatus (26%), Amblyomma variegatum (23%), Rhipicephalus sanguineus s.l. (4.8%), of Haemaphysalis leachi group (4.6%), Hyalomma truncatum (2.6%), Hyalomma rufipes (1.7%), Rhipicephalus muhsamae (1.1%), Rhipicephalus (Boophilus) annulatus (0.6%), Rhipicephalus (Boophilus) decoloratus (0.3%), Ixodes rasus (0.1%), Ixodes spp. (0.2%) and Rhipicephalus spp. (3.3%). Tick legs were subjected to MALDI-TOF MS analyzes, and the spectra of 929 (98.4%) specimens were of good quality. Analysis of these spectra provided intra-species reproducibility and interspecies specificity of MS profiles obtained from the different species. Our in-house MALDI-TOF MS arthropod database was upgraded with spectra from 44 specimens of 10 different tick species. Blind testing of good quality spectra revealed that 99% agreed with the morphological identification. Of these, 96.9% had log score values (LSVs) between 1.73 and 2.57. MALDI-TOF MS also allowed to correct the morphological misidentification of 7 ticks, and to identify 32 engorged ticks that were not morphologically identifiable to the species level. This study supports MALDI-TOF MS as a reliable tool for tick identification and provides new data on tick species identification in Cameroon.

Identification of Algerian field-caught mosquito vectors by MALDI-TOF MS

Vector-borne diseases represent a real threats worldwide, in reason of the lack of vaccine and cure for some diseases. Among arthropod vectors, mosquitoes are described to be the most dangerous animal on earth, resulting in an estimated 725,000 deaths per year due to their borne diseases. Geographical position of Algeria makes this country a high risk area for emerging and re-emerging diseases, such as dengue coming from north (Europe) and malaria from south (Africa). To prevent these threats, rapid and continuous surveillance of mosquito vectors is essential. For this purpose we aimed in this study to create a mosquito vectors locale database using MALDI-TOF mass spectrometry technology for rapid identification of these arthropods. This methodology was validated by testing 211 mosquitoes, including four species (Aedes albopictus, Culex pipiens, Culex quinquefasciatus, and Culiseta longiareolata), in two northern wilayahs of Algeria (Algiers and Bejaia). Species determination by MALDI TOF MS was highly concordant with reference phenotypic and genetic methods. Using this MALDI-TOF MS tool will allow better surveillance of mosquito species able to transmit mosquito borne diseases in Algeria.

Morphological, Molecular and MALDI-TOF MS Identification of Bedbugs and Associated Wolbachia Species in Rural Senegal

Bed bugs are known to carry several microorganisms. The purpose of this study was to assess the prevalence of bed bug infestation in two rural areas of Senegal and determine the species present in the population. A screening was conducted to detect some arthropod associated pathogenic bacteria in bed bugs and to evaluate the prevalence of endosymbiont carriage. One survey took place in 17 villages in Niakhar and two surveys in Dielmo and Ndiop and surroundings area in the same 20 villages. Bed bugs collected were identified morphologically and by MALDI-TOF MS tools. Microorganisms screening was performed by qPCR and confirmed by sequencing. During the survey in the Niakhar region, only one household 1/255 (0.4%) in the village of Ngayokhem was found infested by bed bugs. In a monitoring survey of the surroundings of Dielmo and Ndiop area, high prevalence was found during the two rounds of surveys in 65/314 (21%) in 16/20 villages (January-March) and 93/351 (26%) in 19/20 villages (December). All bed bugs were morphologically identified as the species Cimex hemipterus, of which 285/1,637 (17%) were randomly selected for MALDI-TOF MS analysis and bacteria screening. Among the Bacteria tested only Wolbachia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) DNA was found in 248/276 (90%) of the bedbugs. We briefly describe a high level of non-generalized bed bug infestation in rural Senegal and the diversity of Wolbachia strains carried by C. hemipterus. This study opens perspectives for raising household awareness of bed bug infestations and possibilities for appropriate control.

Performance of MALDI-TOF Mass Spectrometry to Determine the Sex of Mosquitoes and Identify Specific Colonies from French Polynesia

Mosquitoes are the main arthropod vectors of human pathogens. The current methods for mosquito identification include morphological and molecular methods. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), now routinely used for bacterial identification, has recently emerged in the field of entomology. The aim of this study was to use MALDI-TOF MS to identify mosquito colonies from French Polynesia. Five hundred specimens from French Polynesia belonging to three species, Aedes aegypti, Aedes polynesiensis, and Culex quinquefasciatus, were included in the study. Testing the legs of these mosquitoes by MALDI-TOF MS revealed a 100% correct identification of all specimens at the species level. The MALDI-TOF MS profiles obtained allowed differentiation of male from female mosquitoes and the specific identification of female mosquito colonies of the same species but different geographic origin.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: an emerging tool for studying the vectors of human infectious diseases

Arthropod vectors have historically been identified morphologically, and more recently using molecular biology methods. However, both of these methods are time-consuming and require specific expertise and equipment. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, which has revolutionized the routine identification of microorganisms in clinical microbiology laboratories, was recently successfully applied to the identification of arthropod vectors. Since then, the robustness of this identification technique has been confirmed, extended to a large panel of arthropod vectors, and assessed for detecting blood feeding behavior and identifying the infection status in regard to certain pathogenic agents. In this study, we summarize the state-of-the-art of matrix-assisted laser desorption ionization time-of-flight mass spectrometry applied to the identification of arthropod vectors (ticks, mosquitoes, phlebotomine sand-flies, fleas, triatomines, lice and Culicoides), their trophic preferences and their ability to discriminate between infection statuses.

Bartonella spp. Prevalence (Serology, Culture, and PCR) in Sanitary Workers in La Rioja Spain

Bartonella spp. are increasingly implicated in association with a spectrum of zoonotic infectious diseases. One hundred sanitary workers in La Rioja, Spain completed a questionnaire and provided blood specimens for Bartonella spp. serology and Bartonella alpha-Proteobacteria growth medium (BAPGM) enrichment blood culture/PCR. Six immunofluorescence assays (IFA) were performed and aseptically obtained blood specimens were inoculated into liquid BAPGM and subcultured onto blood agar plates. Bartonella DNA was amplified using conventional and real-time PCR assays. The Bartonella spp., strain, or genotype was determined by DNA sequencing. Bartonella seroreactivity was documented in 83.1% and bloodstream infection in 21.6% of participants. Bartonella henselae, B. vinsonii subsp. berkhoffii genotypes I and III, and B. quintana were identified. IFA seroreactivity and PCR positivity were not statistically associated with self-reported symptoms. Our results suggest that exposure to and non-clinical infection with Bartonella spp. may occur more often than previously suspected in the La Rioja region.