M'hammed Sarih

Different cytokine profiles of peripheral blood mononuclear cells from patients with persistent and self-limited hepatitis C virus infection

An imbalance between T helper cell Th1 and Th2 like cytokines has been described in several chronic infectious diseases. In an attempt to characterise the mechanism responsible for viral persistence in hepatitis C virus (HCV)-related chronic infection, we analyzed Th1 cytokines (IL-2, IL-12, IFN-gamma) and Th2 cytokines (IL-4, IL-10) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMC) derived from ten patients with viremic chronic hepatitis C, five healthy HCV seropositive individuals and four HCV seronegative individuals. Cytokine production was determined by enzyme-linked immunosorbent assay (ELISA) after 72 h of stimulation. The results showed that the production of IFN-gamma by PHA-stimulated PBMC was decreased in patients with hepatitis C infection (P=0.05). IL-4 production was not detected in both patients and controls, while no difference was observed for IL-2, IL-10 and IL-12 production between patients and controls. Furthermore, IL-12 and IFN-gamma production was weaker in patients with viremic chronic hepatitis C than in subjects who were able to clear the virus (P=0.01; P=0.03, respectively). These results clearly indicate that a defect both in IL-12 and IFN-gamma production may contribute to the persistence of HCV infection.

Spotted Fever Group Rickettsiae in Ticks, Morocco

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

Detection and Identification of Ehrlichia spp. in Ticks Collected in Tunisia and Morocco

ABSTRACT A broad-range 16S rRNA gene PCR assay followed by partial sequencing of the 16S rRNA gene was used for the detection of members of the family Anaplasmataceae in ticks in North Africa. A total of 418 questing Ixodes ricinus ticks collected in Tunisia and Morocco, as well as 188 Rhipicephalus ticks from dogs and 52 Hyalomma ticks from bovines in Tunisia, were included in this study. Of 324 adult I. ricinus ticks, 16.3% were positive for Ehrlichia spp., whereas only 3.4 and 2.8% of nymphs and larvae, respectively, were positive. A large heterogeneity was observed in the nucleotide sequences. Partial sequences identical to that of the agent of human granulocytic ehrlichiosis (HGE) were detected in I. ricinus and Hyalomma detritum, whereas partial sequences identical to that of Anaplasma platys were detected in Rhipicephalus sanguineus. However, variants of Anaplasma, provisionally designated Anaplasma-like, were predominant in the I. ricinus tick population in Maghreb. Otherwise, two variants of the genus Ehrlichia were detected in I. ricinus and H. detritum. Surprisingly, a variant of Wolbachia pipientis was evidenced from I. ricinus in Morocco. These results emphasized the potential risk of tick bites for human and animal populations in North Africa.

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.

First Isolation of Borrelia burgdorferi Sensu Lato from Ixodes ricinus Ticks in Morocco

To determine the infection rate of Ixodes ricinus (I. ricinus) ticks with Borrelia burgdorferi sensu lato (B. burgdorferi sl) and to assess the frequency of the individual Borrelia species in this tick species, a total of 295 I. ricinus were collected in Taza region (Northeast of Morocco), from January to June 2002. The presence of B. burgdorferi sl was determined by direct fluorescence antibody assay (DFA) and by PCR after culture. B. burgdorferi sl isolates were identified at the species level by restriction fragment length polymorphism analysis of amplified products. The mean rate of I. ricinus infection with B. burgdorferi sl was 47.8%. Isolation attempts in BSK II medium resulted in 26 pure isolates. However, PCR performed on culture medium allowed to identify 82 Borrelia DNAs. B. lusitaniae has been identified from 76 out of 82 infected I. ricinus ticks (92.7%). Three ticks were infected by B. burgdorferi ss, and three other ticks were infected by B. garinii. This is the first report of the presence of B. burgdorferi sl in Morocco and more specifically of B. burgdorferi ss in North Africa.

Borrelia hispanica Relapsing Fever, Morocco

We found that 20.5% of patients with an unexplained fever in northwestern Morocco had tick-borne relapsing fever. Molecular detection specific for the 16S rRNA gene identified Borrelia hispanica. The noncoding intergenic spacer sequence domain showed high sensitivity and good resolution for this species.

Characterization of Borrelia lusitaniae Isolates Collected in Tunisia and Morocco

ABSTRACT Borrelia lusitaniae is a species within the complex Borrelia burgdorferi sensu lato and is infrequently isolated in Europe. In contrast, this species is by far the most predominant in North Africa and in Portugal. In this study, we analyzed the genetic diversity, at several loci, of a large population of isolates from free-living Ixodes ricinus ticks collected in Tunisia and Morocco. We found a moderate diversity of the whole genome by using pulsed-field gel electrophoresis as well as in the ospA gene sequences, compared to a high level of strain homogeneity in the small noncoding ribosomal spacer. In contrast, a high diversity of this locus has been previously reported for Portuguese isolates. We hypothesize that B. lusitaniae strains isolated in North Africa constitute a clone of Portuguese origin.

Epidemiology of Tick-Borne Borreliosis in Morocco

Background The presence in Morocco of Argasid ticks of the Ornithodoros erraticus complex, the vector of tick-borne relapsing fever (TBRF) in North Africa, has been known since 1919, but the disease is rarely diagnosed and few epidemiological data are available. Methodology/Principal Findings Between 2006 and 2011, we investigated the presence of Ornithodoros ticks in rodent burrows in 34 sites distributed across Morocco. We also collected small mammals in 10 sites and we investigated TBRF in febrile patients in Kenitra district. The prevalence of Borrelia infections was assessed by nested PCR amplification in ticks and the brain tissue of small mammals, and by evaluation of thick blood films in patients. A high proportion of burrows were infested with ticks of the O. erraticus complex in all regions of Morocco, with a mean of 39.5% for the whole country. Borrelia infections were found in 39/382 (10.2%) of the ticks and 12/140 (8.6%) of the rodents and insectivores studied by PCR amplification, and 102 patients tested positive by thick blood film. Five small mammalian species were found infected: Dipodillus campestris, Meriones shawi, Gerbillus hoogstrali, Gerbillus occiduus and Atelerix algirus. Three Borrelia species were identified in ticks and/or rodents: B. hispanica, B. crocidurae and B. merionesi. Conclusions/Significance Tick populations belonging to O. erraticus complex are widely distributed in Morocco and a high proportion of ticks and small mammals are infected by Borrelia species. Although rarely diagnosed, TBRF may be a common cause of morbidity in all regions of Morocco.

Coxiella burnetii-positive PCR in febrile patients in rural and urban Africa

OBJECTIVES Q fever has been reported throughout the African continent. The objective of this study was to detect the presence of Coxiella burnetii in febrile patients from Africa. METHODS Blood samples from febrile and non-febrile patients from six African countries and from France were investigated retrospectively for Q fever infection by molecular assays targeting the IS1111 and IS30A spacers. RESULTS We tested 1888 febrile patients from Senegal, Mali, Tunisia, Algeria, Gabon, and Morocco and found one male adult patient (0.3%) infected with C. burnetii in Algeria and six positive patients (0.5%) in Senegal. For one patient from Senegal we determined that the infection was caused by C. burnetii genotype 35. In Senegal, more patients were infected with C. burnetii in Keur Momar Sarr (p=0.002) than in the other locations. Blood samples taken from 500 (51% males) non-febrile people from Senegal and France were all negative. CONCLUSIONS The installation of point-of-care laboratories in rural Africa can be a very effective tool for studying the epidemiology of many infectious diseases.

Bartonella clarridgeiae, B. henselae and Rickettsia felis in fleas from Morocco

Abstract A total of 554 fleas were collected in the Moroccan Casablanca and Tiznit regions from domesticated animals and ruminants between August 2007 and October 2008 and were tested for the presence of Rickettsia spp. and Bartonella spp. using molecular methods. For the first time in Morocco, we found Rickettsia felis, the agent of flea-borne spotted fever in Ctenocephalides felis; B. henselae, an agent of cat scratch disease; and Bartonella clarridgeiae, a cat pathogen and potentially a human pathogen.