Oleg Mediannikov | Aix-Marseille University (original) (raw)
Papers by Oleg Mediannikov
Parasites & Vectors
Background Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bl... more Background Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bloodsucking parasite that co-evolved with their human hosts over thousands of years, thus providing a valuable source of information to reconstruct the human migration. Pediculosis due to head lice occurred each year throughout the world and several pathogenic bacteria, which are usually associated with body lice, are increasingly detected in them. In Gabon, where this pediculosis is still widespread, there is a lack of data on genetic diversity of head lice and their associated bacteria. Methods This study aimed to investigate the phylogeny of head lice collected in Gabon and their associated bacteria, using molecular tools. Between 26 March and 11 April 2018, 691 head lice were collected from 86 women in Franceville. We studied the genetic diversity of these lice based on the cytochrome b gene, then we screened them for DNA of Bartonella quintana, Borrelia spp., Acinetobacter spp., Yers...
International Journal of Molecular Sciences
The symbiotic Wolbachia are the most sophisticated mutualistic bacterium among all insect-associa... more The symbiotic Wolbachia are the most sophisticated mutualistic bacterium among all insect-associated microbiota. Wolbachia-insect relationship fluctuates from the simple facultative/parasitic to an obligate nutritional-mutualistic association as it was the case of the bedbug-Wolbachia from Cimexlectularius. Understanding this association may help in the control of associated arthropods. Genomic data have proven to be reliable tools in resolving some aspects of these symbiotic associations. Although, Wolbachia appear to be fastidious or uncultivated bacteria which strongly limited their study. Here we proposed Drosophila S2 cell line for the isolation and culture model to study Wolbachia strains. We therefore isolated and characterized a novel Wolbachia strain associated with the bedbug Cimexhemipterus, designated as wChem strain PL13, and proposed Wolbachiamassiliensis sp. nov. strain wChem-PL13 a type strain of this new species from new supergroup T. Phylogenetically, T-supergroup ...
Background Equine vector borne diseases (EVBD) have been considered emerging and reemerging disea... more Background Equine vector borne diseases (EVBD) have been considered emerging and reemerging diseases transmitted by arthropods and most of these diseases have zoonotic concern. This study was designed to screen EVBD in equines and their vectors using molecular analyses and identify vectors by MALDI-TOF and molecular techniques.Methods A total of 335 blood samples were collected from apparently healthy equines (320 from horses and 15 from donkeys) from Cairo and Beni-Suef provinces in Egypt. A total of 166 arthropods (105 sucking flies and 61 ticks) were collected from the same animals. MALDI-TOF and molecular techniques were used to confirm the findings of morphological identification of vector. Quantitative PCR and Standard PCR coupled with sequencing were performed in equines and vectors DNA for screening multiple pathogens.Results MALDI-TOF and molecular techniques confirmed that Hippoposca equina (louse fly), Rhipicephalus annulatus (Rh. annulatus) and Rh. microplus ixodid ticks...
Vector-Borne and Zoonotic Diseases
Comparative Immunology, Microbiology and Infectious Diseases
Parasite
Canine dirofilarioses are nematode infections caused by two species of the genus Dirofilaria: D. ... more Canine dirofilarioses are nematode infections caused by two species of the genus Dirofilaria: D. immitis and D. repens. We describe here an outbreak of D. immitis and D. repens infection in military working dogs (MWDs) housed in a kennel in the Indre department (centre of France). Out of a total of 17 dogs, 6 (35.2%) tested positive for D. immitis, D. repens or both parasites. Infested dogs were treated and prophylactic measures were implemented for the entire kennel staff. To our knowledge, this is the first documented description of an outbreak of canine cardiopulmonary dirofilariasis in the center of France, unlike in the south of this country, where D. immitis and D. repens dirofilariasis are enzootic. In France, as mosquito vectors expand their territory and new non-native vectors are introduced, it is likely that the distribution area of these two diseases of domestic and wild carnivores will be wider and underestimated.
Vector-Borne and Zoonotic Diseases
New Microbes and New Infections
Comparative Immunology, Microbiology and Infectious Diseases, 2016
In Senegal, domestic ruminants play a vital role in the economy and agriculture and as a food sou... more In Senegal, domestic ruminants play a vital role in the economy and agriculture and as a food source for people. Bartonellosis in animals is a neglected disease in the tropical regions, and little information is available about the occurrence of this disease in African ruminants. Human bartonellosis due to Bartonella quintana has been previously reported in Senegal. In this study, 199 domestic ruminants, including 104 cattle, 43 sheep, and 52 goats were sampled in villages from the Senegalese regions of Sine Saloum and Casamance. We isolated 29 Bartonella strains, all exclusively from cattle. Molecular and genetic characterization of isolated strains identified 27 strains as Bartonella bovis and two strains as potentially new species. The strains described here represent the first Bartonella strains isolated from domestic ruminants in Senegal and the first putative new Bartonella sp. isolated from cattle in Africa.
Ticks and tick-borne diseases, 2012
Eighty Ixodes ricinus ticks collected in the Rovinka forest in Slovakia were tested by real-time ... more Eighty Ixodes ricinus ticks collected in the Rovinka forest in Slovakia were tested by real-time and routine single-step PCR for the presence of different pathogenic and endosymbiotic bacteria. No evidence of Coxiella burnetii, Diplorickettsia massiliensis, or Bartonella spp. was found. However, we identified, as the pathogenic bacteria, Anaplasma phagocytophilum in 8%, Rickettsia helvetica in 11%, Borrelia afzelii in 9%, Bo. garinii in 8%, Bo. burgdorferi sensu stricto in 5%, Bo. valaisiana in 3%, and Bo. miyamotoi in 1% of ticks. Other bacteria with unknown or suspected pathogenicity for humans were also identified: Arsenophonus nasoniae in 25%, Spiroplasma ixodetis in 3%, Candidatus Midichloria mitochondrii in 4%, Wolbachia aff. pipientis in 14%, and Ehrlichia muris in 3% of ticks. A. nasoniae was found almost exclusively in nymphs, and E. muris was only found in adult ticks. In total, 65% of ticks contained at least one species of bacteria, and 16% contained 2 or more species.
Viruses
Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of... more Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of the zoonotic or cross-species transmission of AdVs. As with humans, AdV infections in animals can cause diseases that range from asymptomatic to fatal. The aim of this study was to investigate the occurrence and diversity of AdVs in: (i) fecal samples of apes and monkeys from different African countries (Republic of Congo, Senegal, Djibouti and Algeria), (ii) stool of humans living near gorillas in the Republic of Congo, in order to explore the potential zoonotic risks. Samples were screened by real-time and standard PCRs, followed by the sequencing of the partial DNA polymerase gene in order to identify the AdV species. The prevalence was 3.3 folds higher in NHPs than in humans. More than 1/3 (35.8%) of the NHPs and 1/10 (10.5%) of the humans excreted AdVs in their feces. The positive rate was high in great apes (46%), with a maximum of 54.2% in chimpanzees (Pan troglodytes) and 35.9% ...
Microorganisms
In French Guiana, canine heartworm disease is well known, but the diversity of filarial parasites... more In French Guiana, canine heartworm disease is well known, but the diversity of filarial parasites of dogs remains largely unknown. A total of 98 canine blood samples from Cayenne and Kourou were assessed by a blood wet mount preparation, heartworm antigen test and molecular exploration of filarioid and Wolbachia DNAs, followed by a multiplex species-specific qPCR’s identification and a subsequent sequencing analysis. Thereafter, a phylogeny based on maximum likelihood was carried out to facilitate specific identification. Five dogs were microfilaremic. Heartworm antigens were detected in 15 (15.3%) dogs. Of these, six (6.1%) were considered as occult infections as neither microfilariae nor Dirofilaria immitis DNA were detected. The 11 (11.2%) D. immitis isolates corresponded to a low virulent strain. Six of the D. immitis isolates were positive for Wolbachia endosymbionts of D. immitis belonging to the clade C DNA. Acanthocheilonema reconditum DNA was detected in 3 (3.1%) samples. O...
Pathogens
Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides... more Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4 Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h an...
Surveillance of SARS-CoV-2 infection among sheltered homeless and other vulnerable people might p... more Surveillance of SARS-CoV-2 infection among sheltered homeless and other vulnerable people might provide the information needed to prevent its spread within accommodation centres. In March-April, we enrolled 411 homeless individuals, 77 asylum-seekers, 58 people living in precarious conditions, and 152 employees working in these accommodation centres and collected nasal samples. SARS-CoV-2 carriage was assessed by quantitative PCR. Overall, 49 (7.0%) people were positive for SARS-CoV-2, including 37 homeless individuals (of 411, 9.0%), 12 employees (of 152, 7.9%). SARS-CoV-2 positivity correlated with symptoms, although 51% of positive patients did not report respiratory symptoms or fever. Among homeless people, being young (18-34 years) (OR: 3.83 [1.47-10.0], p=0.006) and being housed in one specific shelter (OR: 9.13 [4.09-20.37], p<0.0001) were independent factors associated with the SARS-CoV-2 positivity rates (11.4% and 20.6%, respectively). The survey reveals the role of col...
Rodents are known to be reservoir hosts for at least 60 zoonotic diseases and are known to play a... more Rodents are known to be reservoir hosts for at least 60 zoonotic diseases and are known to play an important role in their transmission and spreading in different ways. We sampled different rodent communities within and around human settlements in Northern Senegal, an area subjected to major environmental transformations associated with global changes. Herein, we conducted an epidemiological study on their bacterial communities.One hundred and seventy-one (171) invasive and native rodents were captured, 50 from outdoors trapping sites and 121 rodents from indoors habitats, consisting on 5 species. DNA of thirteen pathogens have been successfully screened on the rodent’s spleens. We found: 2.3% of positive spleens to Piroplasmida and amplified one which gives a potentially new species Candidatus “Theileria senegalensis”; 9.35% of Bartonella spp. and amplified 10, giving three genotypes. 3.5% of filariasis species; 18.12% of Anaplasmataceae species and amplified only 5, giving a new p...
International Journal of Infectious Diseases
Frontiers in Public Health
New Microbes and New Infections
Parasites & Vectors
Background Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bl... more Background Pediculus humanus, which includes two ecotypes (body and head lice), is an obligate bloodsucking parasite that co-evolved with their human hosts over thousands of years, thus providing a valuable source of information to reconstruct the human migration. Pediculosis due to head lice occurred each year throughout the world and several pathogenic bacteria, which are usually associated with body lice, are increasingly detected in them. In Gabon, where this pediculosis is still widespread, there is a lack of data on genetic diversity of head lice and their associated bacteria. Methods This study aimed to investigate the phylogeny of head lice collected in Gabon and their associated bacteria, using molecular tools. Between 26 March and 11 April 2018, 691 head lice were collected from 86 women in Franceville. We studied the genetic diversity of these lice based on the cytochrome b gene, then we screened them for DNA of Bartonella quintana, Borrelia spp., Acinetobacter spp., Yers...
International Journal of Molecular Sciences
The symbiotic Wolbachia are the most sophisticated mutualistic bacterium among all insect-associa... more The symbiotic Wolbachia are the most sophisticated mutualistic bacterium among all insect-associated microbiota. Wolbachia-insect relationship fluctuates from the simple facultative/parasitic to an obligate nutritional-mutualistic association as it was the case of the bedbug-Wolbachia from Cimexlectularius. Understanding this association may help in the control of associated arthropods. Genomic data have proven to be reliable tools in resolving some aspects of these symbiotic associations. Although, Wolbachia appear to be fastidious or uncultivated bacteria which strongly limited their study. Here we proposed Drosophila S2 cell line for the isolation and culture model to study Wolbachia strains. We therefore isolated and characterized a novel Wolbachia strain associated with the bedbug Cimexhemipterus, designated as wChem strain PL13, and proposed Wolbachiamassiliensis sp. nov. strain wChem-PL13 a type strain of this new species from new supergroup T. Phylogenetically, T-supergroup ...
Background Equine vector borne diseases (EVBD) have been considered emerging and reemerging disea... more Background Equine vector borne diseases (EVBD) have been considered emerging and reemerging diseases transmitted by arthropods and most of these diseases have zoonotic concern. This study was designed to screen EVBD in equines and their vectors using molecular analyses and identify vectors by MALDI-TOF and molecular techniques.Methods A total of 335 blood samples were collected from apparently healthy equines (320 from horses and 15 from donkeys) from Cairo and Beni-Suef provinces in Egypt. A total of 166 arthropods (105 sucking flies and 61 ticks) were collected from the same animals. MALDI-TOF and molecular techniques were used to confirm the findings of morphological identification of vector. Quantitative PCR and Standard PCR coupled with sequencing were performed in equines and vectors DNA for screening multiple pathogens.Results MALDI-TOF and molecular techniques confirmed that Hippoposca equina (louse fly), Rhipicephalus annulatus (Rh. annulatus) and Rh. microplus ixodid ticks...
Vector-Borne and Zoonotic Diseases
Comparative Immunology, Microbiology and Infectious Diseases
Parasite
Canine dirofilarioses are nematode infections caused by two species of the genus Dirofilaria: D. ... more Canine dirofilarioses are nematode infections caused by two species of the genus Dirofilaria: D. immitis and D. repens. We describe here an outbreak of D. immitis and D. repens infection in military working dogs (MWDs) housed in a kennel in the Indre department (centre of France). Out of a total of 17 dogs, 6 (35.2%) tested positive for D. immitis, D. repens or both parasites. Infested dogs were treated and prophylactic measures were implemented for the entire kennel staff. To our knowledge, this is the first documented description of an outbreak of canine cardiopulmonary dirofilariasis in the center of France, unlike in the south of this country, where D. immitis and D. repens dirofilariasis are enzootic. In France, as mosquito vectors expand their territory and new non-native vectors are introduced, it is likely that the distribution area of these two diseases of domestic and wild carnivores will be wider and underestimated.
Vector-Borne and Zoonotic Diseases
New Microbes and New Infections
Comparative Immunology, Microbiology and Infectious Diseases, 2016
In Senegal, domestic ruminants play a vital role in the economy and agriculture and as a food sou... more In Senegal, domestic ruminants play a vital role in the economy and agriculture and as a food source for people. Bartonellosis in animals is a neglected disease in the tropical regions, and little information is available about the occurrence of this disease in African ruminants. Human bartonellosis due to Bartonella quintana has been previously reported in Senegal. In this study, 199 domestic ruminants, including 104 cattle, 43 sheep, and 52 goats were sampled in villages from the Senegalese regions of Sine Saloum and Casamance. We isolated 29 Bartonella strains, all exclusively from cattle. Molecular and genetic characterization of isolated strains identified 27 strains as Bartonella bovis and two strains as potentially new species. The strains described here represent the first Bartonella strains isolated from domestic ruminants in Senegal and the first putative new Bartonella sp. isolated from cattle in Africa.
Ticks and tick-borne diseases, 2012
Eighty Ixodes ricinus ticks collected in the Rovinka forest in Slovakia were tested by real-time ... more Eighty Ixodes ricinus ticks collected in the Rovinka forest in Slovakia were tested by real-time and routine single-step PCR for the presence of different pathogenic and endosymbiotic bacteria. No evidence of Coxiella burnetii, Diplorickettsia massiliensis, or Bartonella spp. was found. However, we identified, as the pathogenic bacteria, Anaplasma phagocytophilum in 8%, Rickettsia helvetica in 11%, Borrelia afzelii in 9%, Bo. garinii in 8%, Bo. burgdorferi sensu stricto in 5%, Bo. valaisiana in 3%, and Bo. miyamotoi in 1% of ticks. Other bacteria with unknown or suspected pathogenicity for humans were also identified: Arsenophonus nasoniae in 25%, Spiroplasma ixodetis in 3%, Candidatus Midichloria mitochondrii in 4%, Wolbachia aff. pipientis in 14%, and Ehrlichia muris in 3% of ticks. A. nasoniae was found almost exclusively in nymphs, and E. muris was only found in adult ticks. In total, 65% of ticks contained at least one species of bacteria, and 16% contained 2 or more species.
Viruses
Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of... more Non-human primates (NHPs) are known hosts for adenoviruses (AdVs), so there is the possibility of the zoonotic or cross-species transmission of AdVs. As with humans, AdV infections in animals can cause diseases that range from asymptomatic to fatal. The aim of this study was to investigate the occurrence and diversity of AdVs in: (i) fecal samples of apes and monkeys from different African countries (Republic of Congo, Senegal, Djibouti and Algeria), (ii) stool of humans living near gorillas in the Republic of Congo, in order to explore the potential zoonotic risks. Samples were screened by real-time and standard PCRs, followed by the sequencing of the partial DNA polymerase gene in order to identify the AdV species. The prevalence was 3.3 folds higher in NHPs than in humans. More than 1/3 (35.8%) of the NHPs and 1/10 (10.5%) of the humans excreted AdVs in their feces. The positive rate was high in great apes (46%), with a maximum of 54.2% in chimpanzees (Pan troglodytes) and 35.9% ...
Microorganisms
In French Guiana, canine heartworm disease is well known, but the diversity of filarial parasites... more In French Guiana, canine heartworm disease is well known, but the diversity of filarial parasites of dogs remains largely unknown. A total of 98 canine blood samples from Cayenne and Kourou were assessed by a blood wet mount preparation, heartworm antigen test and molecular exploration of filarioid and Wolbachia DNAs, followed by a multiplex species-specific qPCR’s identification and a subsequent sequencing analysis. Thereafter, a phylogeny based on maximum likelihood was carried out to facilitate specific identification. Five dogs were microfilaremic. Heartworm antigens were detected in 15 (15.3%) dogs. Of these, six (6.1%) were considered as occult infections as neither microfilariae nor Dirofilaria immitis DNA were detected. The 11 (11.2%) D. immitis isolates corresponded to a low virulent strain. Six of the D. immitis isolates were positive for Wolbachia endosymbionts of D. immitis belonging to the clade C DNA. Acanthocheilonema reconditum DNA was detected in 3 (3.1%) samples. O...
Pathogens
Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides... more Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4 Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h an...
Surveillance of SARS-CoV-2 infection among sheltered homeless and other vulnerable people might p... more Surveillance of SARS-CoV-2 infection among sheltered homeless and other vulnerable people might provide the information needed to prevent its spread within accommodation centres. In March-April, we enrolled 411 homeless individuals, 77 asylum-seekers, 58 people living in precarious conditions, and 152 employees working in these accommodation centres and collected nasal samples. SARS-CoV-2 carriage was assessed by quantitative PCR. Overall, 49 (7.0%) people were positive for SARS-CoV-2, including 37 homeless individuals (of 411, 9.0%), 12 employees (of 152, 7.9%). SARS-CoV-2 positivity correlated with symptoms, although 51% of positive patients did not report respiratory symptoms or fever. Among homeless people, being young (18-34 years) (OR: 3.83 [1.47-10.0], p=0.006) and being housed in one specific shelter (OR: 9.13 [4.09-20.37], p<0.0001) were independent factors associated with the SARS-CoV-2 positivity rates (11.4% and 20.6%, respectively). The survey reveals the role of col...
Rodents are known to be reservoir hosts for at least 60 zoonotic diseases and are known to play a... more Rodents are known to be reservoir hosts for at least 60 zoonotic diseases and are known to play an important role in their transmission and spreading in different ways. We sampled different rodent communities within and around human settlements in Northern Senegal, an area subjected to major environmental transformations associated with global changes. Herein, we conducted an epidemiological study on their bacterial communities.One hundred and seventy-one (171) invasive and native rodents were captured, 50 from outdoors trapping sites and 121 rodents from indoors habitats, consisting on 5 species. DNA of thirteen pathogens have been successfully screened on the rodent’s spleens. We found: 2.3% of positive spleens to Piroplasmida and amplified one which gives a potentially new species Candidatus “Theileria senegalensis”; 9.35% of Bartonella spp. and amplified 10, giving three genotypes. 3.5% of filariasis species; 18.12% of Anaplasmataceae species and amplified only 5, giving a new p...
International Journal of Infectious Diseases
Frontiers in Public Health
New Microbes and New Infections