Spotted Fever Group Rickettsiae in Ticks, Morocco

Identified rickettsiae were 4 pathogens, 2 suspected pathogens, and 1 incompletely described species

Culex pipiens, an Experimental Efficient Vector of West Nile and Rift Valley Fever Viruses in the Maghreb Region

West Nile fever (WNF) and Rift Valley fever (RVF) are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV) circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV) re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 107.8 and 108.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14–21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology

Molecular evidence of Culex pipiens form molestus and hybrids pipiens/molestus in Morocco, North Africa

International audienceBackgroundCulex pipiens L. is the most widespread mosquito vector in temperate regions including North Africa. Cx. pipiens has two recognized forms or biotypes; pipiens and molestus are morphologically indistinguishable with distinct behavior and physiology that may influence their vectorial status. In our study, we prospected for the different forms of Cx. pipiens in Morocco.MethodsCx. pipiens larvae were collected in 9 sites throughout Morocco during summer 2010 and reared until imago stage. Cx. pipiens was identified using diagnostic primers designed for the flanking region of microsatellite CQ11.ResultsWe established the presence of both forms of Cx. pipiens and their hybrids in Morocco.ConclusionsMolecular identification provides the first evidence of the presence of Cx. pipiens form molestus in Morocco and hybrids between pipiens and molestus forms in North Africa. The epidemiological implications of our findings are discussed

Potential of Aedes albopictus to cause the emergence of arboviruses in Morocco

International audienceIn 2015, the mosquito Aedes albopictus was detected in Rabat, Morocco. This invasive species can be involved in the transmission of more than 25 arboviruses. It is known that each combination of mosquito population and virus genotype leads to a specific interaction that can shape the outcome of infection. Testing the vector competence of local mosquitoes is therefore a prerequisite to assess the risks of emergence. A field-collected strain of Ae. albopictus from Morocco was experimentally infected with dengue (DENV), chikungunya (CHIKV), zika (ZIKV) and yellow fever (YFV) viruses. We found that this species can highly transmit CHIKV and to a lesser extent, DENV, ZIKV and YFV. Viruses can be detected in mosquito saliva at day 3 (CHIKV), day 14 (DENV and YFV), and day 21 (ZIKV) post-infection. These results suggest that the local transmission of these four arboviruses by Ae. albo-pictus newly introduced in Morocco is a likely scenario. Trial registration: ClinicalTrials.gov APAFIS#6573-201606l412077987v2

Characteristic of <i>Culex pipiens</i> sites sampled in Morocco, Algeria and Tunisia.

<p>Characteristic of <i>Culex pipiens</i> sites sampled in Morocco, Algeria and Tunisia.</p

Localization of <i>Culex pipiens</i> samples collected in 2010 in the Maghreb (Morocco, Algeria and Tunisia).

<p>Localization of <i>Culex pipiens</i> samples collected in 2010 in the Maghreb (Morocco, Algeria and Tunisia).</p

Transmission rate and mean titer of infectious viral particles present in saliva of <i>Culex pipiens</i> at different days after ingestion of an infectious blood-meal containing WNV (A) and RVFV (B).

<p>We exposed a <i>Culex pipiens</i> colony, Tabarka (Tunisia) to an infectious blood-meal containing 10^7.8 PFU/mL of WNV or 10^8.5 PFU/mL of RVFV. At day 3, 6, 9, 14 and 21 post-infection, 20 females were analyzed. Saliva were collected using the forced salivation technique. After removing wings and legs, the proboscis of mosquitoes was inserted into 20 µL tip filled with 5 µL of Fetal Bovine Serum (FBS). After 45 min, medium containing the saliva was collected into 45 µL of L15 medium. The number of infectious particles per saliva was estimated by titration on Vero cells and expressed as log₁₀PFU/saliva. Lines refer to TR and bars to Log10 pfu/saliva.</p

Disseminated infection rate, Transmission rate and mean titer of infectious viral particles present in saliva of <i>Culex pipiens</i> at day 14 (A,B and C) and 21 (D,E and F) post-infection with RVFV.

<p>F1 mosquitoes (autogenous AU and anautogenous AN) were orally challenged with RVFV at a titer of 10^8.5 PFU/mL using an artificial feeding system. After completion of the blood-meal, mosquitoes were maintained in BSL-3 insectaries at 28°C. At day 14 pi and day 21 pi, saliva was collected from surviving females using the forced salivation technique. The number of infectious viral particles present in saliva was estimated by plaque assay on Vero cells. After salivation, females were tested for the presence of RVFV on head squashes by IFA. In brackets, the number of mosquitoes tested. Error bars show the confidence interval (95%) for DIR and TR, and the standard deviation for Log10 pfu/saliva.</p

Disseminated infection rate (A), Transmission rate (B) and mean titer of infectious viral particles present in saliva (C) of <i>Culex pipiens</i> challenged with WNV.

<p>F1 mosquitoes (autogenous AU and anautogenous AN) were orally challenged with WNV at a titer of 10^7.8 PFU/mL using an artificial feeding system. After completion of the blood-meal, mosquitoes were maintained in BSL-3 insectaries at 28°C. At day 14 pi, saliva was collected from surviving females using the forced salivation technique. The number of infectious viral particles present in saliva was estimated by plaque assay on Vero cells. After salivation, females were tested for the presence of WNV on head squashes by IFA. p<0.05, Fisher’s exact test. In brackets, the number of mosquitoes tested. Error bars show the confidence interval (95%) for DIR and TR, and the standard deviation for Log10 pfu/saliva.</p