Biomedical subjects

Claire Garros

Publications and source records attributed to Claire Garros.

6 recordsLinked to original sources

PubMed2006

Impact of the Rift Valley on restriction fragment length polymorphism typing of the major African malaria vector Anopheles funestus (Diptera: Culicidae).

Anopheles funestus Giles (Diptera: Culicidae) is one of Africa's major malaria vectors. To understand population structure within An. funestus, various molecular markers have recently been developed. We investigated the impact of the Rift Valley on one such molecular marker, a polymerase chain reaction-restriction fragment length polymorphism (RFLP). This system distinguishes An. funestus populations into types M, W, and MW. Generally, these types correlate between geographical location and RFLP type, whereby M associates essentially with eastern Africa, W with western and central Africa, and MW with southern Africa. In total, 606 specimens were screened from 12 countries. Specimens from southern African localities were of the expected MW-type with the exception of the sample from Malawi, which showed all three types. The specimens from Tanzania showed the M- and MW-types, whereas specimens from Kenya showed M- and W-types. We also recorded different RFLP types not recorded previously. Type Y was recorded in Malawi, and Z-type was recorded from four localities: Angola, Malawi, Ghana, and Zambia.

Africa, Eastern↗

PubMed2006

How reliable is the humeral pale spot for identification of cryptic species of the Minimus Complex?

The Anopheles minimus Complex Theobald (Diptera: Culicidae) is composed of the 3 sibling species A, C, and E. The malaria vectors An. minimus A and C are distributed over the Southeast Asian region, whereas species E is restricted to the Ryukyu Japanese Islands. Because species A and C can be sympatric and present specific behaviors and have a role in malaria transmission, it is important to differentiate them. The literature mentioned the presence of a presector pale spot on the wing costa of An. minimus A, whereas species C may exhibit both presector and humeral pale spots. However, the reliability of their diagnostic power has not been established over large temporal and geographic surveys. From the analyses of 9 populations throughout Southeast Asia, including published data and field populations from 2 sites in Thailand, we showed that the wing patterns present spatial and temporal variations that make these two morphological characters unreliable for the precise identification of An. minimus A and C. Therefore, molecular identification remains the most efficient method to obtain an unambiguous differentiation of these 2 species. Correct species identification is essential and mandatory for any relevant study on the Minimus Complex and for the application of successful control strategies.

Animals↗

PubMed2005

Systematics and biogeographical implications of the phylogenetic relationships between members of the funestus and minimus groups of Anopheles (Diptera: Culicidae).

The Afrotropical Funestus and the Oriental-African Minimus Groups of the Myzomyia Series of Anopheles subgenus Cellia are considered distinct only because of their geographical separation. For the first time, a phylogenetic study was done on six Oriental and four Afrotropical species based on the comparison of ribosomal (ITS2, D3) and mitochondrial (COI) nucleotide sequences. Both maximum parsimony (MP) and maximum likelihood (ML) analyses revealed that the groups form a monophyletic assemblage containing four clades. The inclusion of Afrotropical An. leesoni with the Oriental species was confirmed, whereas An. rivulorum, also an Afrotropical species, was placed in a basal position relative to the African and Oriental species. The biogeography of the Afrotropical and Oriental species was examined in relation to the phylogeny and estimates of divergence time. Divergence events correspond to periods of major tectonic movement as well as periods of great aridity or humidity.

Animals↗

PubMed2005

Morphological assessment and molecular phylogenetics of the Funestus and Minimus groups of Anopheles (Cellia).

A morphological comparison and molecular study of the Afrotropical Funestus and Afro-Oriental Minimus groups within the Myzomyia series of Anopheles (Cellia) was conducted to determine their phylogenetic affinities. Relationships were investigated using morphological characters and ribosomal (D3) and mitochondrial (COII) nucleotide sequences. Cross-identification of specimens from one group by using keys for the other group confirmed their morphological similarity, i.e., members of one group shared the key characters with members of the other group. Molecular analyses recognized five clades, not strictly related to geographical distribution: the Aconitus, Culicifacies, Funestus, Minimus, and Rivulorum subgroups. Morphological observations were congruent with the results of molecular analyses. Anopheles leesoni, an Afrotropical species, is closely related to the Oriental Minimus complex, and these taxa share a close relationship with the Fluviatilis complex that occurs from the Arabian Peninsula through India. The immature and adult stages of An. rivulorum in Africa bear morphological characters that distinguish this species from members of the Afrotropical Funestus subgroup. A composite scheme of classification based on the results and previously published information is proposed for the two groups. It is noted that An. fluviatilis species S is conspecific with An. minimus species C.

Animals↗

PubMed2005

First record of Anopheles minimus C and significant decrease of An. minimus A in central Vietnam.

Before August 1998, in the Khanh Phu commune (central Vietnam), Anopheles minimus s.l. individuals were identified as species A and showed the typical species A wing form. After a significant decrease over the 3 years 1999-2001, an increase in 2002 of An. minimus s.l. possessing a different wing pattern was observed. To determine the specific status of the An. minimus species collected in 2002 and to follow changes in the species composition, an allele-specific polymerase chain reaction was applied to samples collected from 1993 to 2002. This study reports the first record of An. minimus C in central Vietnam and, since 1998, a significant reduction of An. minimus A that coincided with the wide use of permethrin-treated bednets. This change in anopheline composition may have important consequences on malaria transmission. This work shows that the geographic distribution of malaria vectors in southeast Asia is only partially known and highlights the importance of species identification for understanding changes in the vector composition as a result of selective vector control.

Animals↗

PubMed2004

A single multiplex assay to identify major malaria vectors within the African Anopheles funestus and the Oriental An. minimus groups.

The African Anopheles funestus and the Oriental An. minimus groups are closely related and composed of major malaria vectors in Africa and Southeast Asia, respectively. None of the species of either the An. funestus or the An. minimus group can be identified with absolute certainty using the adult morphology. Polymorphisms present on the internal transcribed spacer 2 (ITS2) of ribosomal DNA allowed the development of 10 primers that combined with an universal forward primer lead to a simple and sensitive multiplex allele-specific polymerase chain reaction (AS-PCR). Moreover, the possible additional amplification of the entire ITS2 allows one to detect other anopheline species in sympatry with members of both groups not included in this assay and serves as a control band. This universal PCR method permits the discrimination of 10 species within the subgenus Cellia, among which figure three major malaria vectors, and constitutes a very efficient and powerful tool to improve our knowledge on these species distribution and biology. Not only restricted to anophelines, this AS-PCR could also be developed and applied to other insect groups.

Africa↗