Habib Mezhoud

First detection of Leishmania killicki (Kinetoplastida, Trypanosomatidae) in Ctenodactylus gundi (Rodentia, Ctenodactylidae), a possible reservoir of human cutaneous leishmaniasis in Tunisia

BackgroundLeishmania killicki was originally described in 1980 in southeast Tunisia. It was also recently reported in Lybia and Algeria. Nevertheless, neither vector nor reservoirs of this parasite are known. The identification of the vector and the animal reservoir host of L. killicki is critical for the establishment of an efficient control strategy.Findingsblood, popliteal lymph node, spleen, bone marrow, liver and skin were collected from 50 rodents in 2009 in south western Tunisia. Samples were smeared onto glass slides, cultured on NNN medium and tested by polymerase chain reaction for Leishmania detection. Parasites were detected by PCR from 10 Psammomys obesus and from two Ctenodactylus gundi. Parasite identification was performed simultaneously by internal transcribed spacer 1 PCR-RFLP and by PCR sequencing. Both Leishmania major and Leishmania killicki were identified from infected Psammomys and Ctenodactylus gundi respectively.ConclusionThis is the first report of Leishmania killicki identified from Ctenodactylus gundi in Tunisia. This result supports the assumption that C. gundi is a potential reservoir for Leishmania killicki.

Molecular Identification of Echinococcus granulosus in Tunisia: First Record of the Buffalo Strain (G3) in Human and Bovine in the Country

It has been demonstrated that human hydatidosis was generally due to G1 genotype of Echinococcus granulosus throughout the world. Nevertheless, some other genotypes, such as G3, were recently identified for human cyst. The present work confirms the predominance of the sheep strain G1 in humans, bovine and ovine and demonstrates for the first time the occurrence of the buffalo strain G3 in human and bovine in Tunisia.

Infection of dogs with Echinococcus granulosus: causes and consequences in an hyperendemic area

BackgroundTunisia is a hyper endemic country for human echinococcosis. The infection is transmitted via the eggs of Echinococcus granulosus which are passed in the faeces of the definitive canid host.MethodsThis study evaluated the contamination rate of the dog faeces in different climatic conditions at eight different geographic regions throughout Tunisia. Dog faecal samples were collected from the soil and the Echinococcus eggs were identified using microscopic and molecular (Eg1121/1122 PCR, Egss1 PCR and Nad1 PCR-RFLP) tools.ResultsThe contamination index of dog faeces by E. granulosus eggs ranged from 8.3% to 41.3% depending on the region. Comparisons of the dog faecal contamination rate against human incidence found them to be independent. Neither human prevalence nor dog contamination index appeared to be related to climatic conditions or geographic characteristics. The genetic variability of E. granulosus samples was different within each region but was not related to geographic distance which is indicative of local divergent evolutions rather than isolation by distance.ConclusionsA high environmental dog contamination index does not necessarily correspond to high prevalence in humans as transmission is strongly linked to human behavior and hygiene.

Transmission of Visceral Leishmaniasis in a Previously Non-Endemic Region of Tunisia: Detection of Leishmania Dna in Phlebotomus perniciosus

ABSTRACT: Visceral leishmaniasis (VL) has been endemic in northern Tunisia and has occurred sporadically in the center of Tunisia. Recently, there have been several cases from areas known to be free of VL. We report in this work all human and canine cases of VL recorded between 2003 and 2011 and an entomological study of phlebotomine fauna in a previously non-endemic region. Sixty-three cases of VL were diagnosed and identified as L. infantum using several different methods. Eight species of 179 sand flies were caught and identified by both morphological and molecular methods. Two genera were present, Phlebotomus and Sergentomya, with an abundance of the subgenus Phlebotomus (Larrousius) spp., a classic vector of VL in Tunisia. Moreover, Leishmania DNA was detected in seven unfed Phlebotomus pernicousus and L. infantum was identified in three of them. This result confirms the establishment of a transmission cycle of VL in the studied region by the coexistence of infected vectors with infected hosts.

Étude rétrospective de la distribution et de la fertilité des kystes hydatiques chez l’enfant en Tunisie

PURPOSE OF THE STUDY Our aim was to study the distribution and the fertility of the hydatid cysts in function of the age and the sex of patients and to identify the strain(s) responsible(s) of the children hydatidosis. PATIENTS AND METHODS We have analyzed a total of 241 cysts coming from 195 children aged 2 to 16 years operated in the CHU F. Bourguiba of Monastir during the period from November 1999 to December 2009. For each cyst, the localization and the fertility of the métacestode as well as age, sex and origin of the patient are listed. Identification of strains was carried out by PCR/RFLP and has targeted the ribosomal gene ITS1. RESULTS The lung was the primary localization of cyst (61.8%) followed by the liver (34.85%). The greatest number of cases is observed in the age groups 4-9 years (138 cases) where childrens infection is more frequent in the male than in the female sex. The fertility of the cyst was independent of its site or its size and no incidence of age of children was detected. The G1 sheep strain is responsible for the contamination of children. CONCLUSION The cystic echinococcosis described as a young adult disease may actually observed at any age and remains a serious problem of public health in Tunisia.

Development of a polymerase chain reaction-restriction fragment length polymorphism assay for Leishmania major/Leishmania killicki/Leishmania infantum discrimination from clinical samples, application in a Tunisian focus.

Topoisomerase II gene of Leishmania genus was used to develop a molecular tool for detection and species differentiation of Leishmania from clinical samples. Identification was achieved by a polymerase chain reaction followed by digestion with 2 restriction endonucleases BstU1 and Taq1. Despite the relatively low sensitivity, it is able to differentiate between 3 complexes responsible for cutaneous leishmaniasis.

Blood meal analysis of culicoides (Diptera: ceratopogonidae) in central Tunisia.

To evaluate the host preferences of Culicoides species (Diptera: Ceratopogonidae) in Central Tunisia, we identified the source of blood meals of field collected specimens by sequencing of the cytochrome b (cyt b) mitochondrial locus and Prepronociceptine single copy nuclear gene. The study includes the most common and abundant livestock associated species of biting midges in Tunisia: C. imicola, C. jumineri, C. newsteadi, C. paolae, C. cataneii, C. circumscriptus, C. kingi, C. pseudojumineri, C. submaritimus, C. langeroni, C. jumineri var and some unidentified C. species. Analysis of cyt b PCR products from 182 field collected blood-engorged females’ midges revealed that 92% of them fed solely on mammalian species, 1.6% on birds, 2.4% on insects and 0.8% on reptiles. The blast results identified the blood origin of biting midges to the species level with exact or nearly exact matches (≥98%). The results confirm the presence of several Culicoides species, including proven vectors in Central Tunisia. Blood meal analyses show that these species will indeed feed on bigger mammals, thereby highlighting the risk that these viruses will be able to spread in Tunisia.

First detection of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in Culicoides spp. (Diptera: Ceratopogonidae).

BackgroundCulicoides (Diptera: Ceratopogonidae) species are known to be the vectors of Bluetongue virus and African Horses Sickness virus (AHSV) in different areas of the world. Nevertheless, other researchers have hypothesized that these arthropods could be involved in the transmission of other pathogens such as Schmallenberg virus, Plasmodium and Leishmania parasites. Identification of the Culicoides’ potential vector competence is crucial in understanding the worldwide Culicoides/Leishmania life cycle.FindingsBlood fed and parous females of biting midges Culicoides spp. were collected between 2009 and 2010 in Central Tunisia. DNA was extracted from individual blood fed Culicoides and used as a template in a genus-specific PCR. Leishmania DNA was detected in 14 Culicoides imicola specimens and one Culicoides circumscriptus. In a second step, parasite identification was performed based on a single copy Topo-isomerase II gene specific amplification and sequencing. Leishmania infantum was identified in two infected Culicoides spp.ConclusionThis is the first report of Leishmania DNA detection from naturally infected wild caught Culicoides spp. Our finding supports the assumption that Culicoides spp. are a potential vector for L. infantum.

Article originalÉtude rétrospective de la distribution et de la fertilité des kystes hydatiques chez l’enfant en TunisieRetrospective study of the distribution and the fertility of hydatid cysts in the child in Tunisia

PURPOSE OF THE STUDY Our aim was to study the distribution and the fertility of the hydatid cysts in function of the age and the sex of patients and to identify the strain(s) responsible(s) of the children hydatidosis. PATIENTS AND METHODS We have analyzed a total of 241 cysts coming from 195 children aged 2 to 16 years operated in the CHU F. Bourguiba of Monastir during the period from November 1999 to December 2009. For each cyst, the localization and the fertility of the métacestode as well as age, sex and origin of the patient are listed. Identification of strains was carried out by PCR/RFLP and has targeted the ribosomal gene ITS1. RESULTS The lung was the primary localization of cyst (61.8%) followed by the liver (34.85%). The greatest number of cases is observed in the age groups 4-9 years (138 cases) where childrens infection is more frequent in the male than in the female sex. The fertility of the cyst was independent of its site or its size and no incidence of age of children was detected. The G1 sheep strain is responsible for the contamination of children. CONCLUSION The cystic echinococcosis described as a young adult disease may actually observed at any age and remains a serious problem of public health in Tunisia.

Environmental Contamination by Echinococcus granulosus sensu lato Eggs in Relation to Slaughterhouses in Urban and Rural Areas in Tunisia

Hydatidosis has become a real concern for health care institutions and animal rearers in Tunisia. The Tunisian endemicity is aggravated by the growing number of dogs and the difficulty of getting rid of contaminated viscera because of the lack of equipment in most slaughterhouses. Therefore, microscopic and molecular tools were applied to evaluate the role of slaughterhouses in canine infection and Echinococcus granulosus sensu lato (s. l.) egg dissemination. Exposure risk to E. granulosus s. l. eggs in urban and rural areas was explored in order to implant preventive and adapted control strategies. Microscopic examinations detected taeniid eggs in 152 amongst 553 fecal samples. The copro-PCR demonstrated that 138 of 152 taeniid samples analyzed were positive for E. granulosus s. l. DNA. PCR-RFLP demonstrated that all isolated samples belonged to E. granulosus sensu stricto (s. s.). An important environmental contamination index (25.0%) by E. granulosus s. l. eggs was demonstrated. The average contamination index from the regions around slaughterhouses (23.3%; 95% CI: 17.7-28.9%) was in the same range as detected in areas located far from slaughterhouses (26.0%, 95% CI: 21.3-30.8%). Echinococcosis endemic areas were extended in both rural (29.9%, 95% CI: 24.8-34.9%) and urban locations (18.1%, 95% CI: 13.0-22.9%). The pathogen dissemination is related neither to the presence/absence of slaughterhouses nor to the location in urban or rural areas, but is probably influenced by human activities (home slaughtering) and behavior towards the infected viscera.