The life cycle and immature stages of Kallima albofasciata, the endemic Oakleaf, in the Andaman Islands (Indian Ocean, Bay of Bengal)

Kallima albofasciata Moore 1877 (Lepidoptera: Nymphalidae), a species of Oakleaf butterfly reported for the first time from the Andaman Islands in 1874, was recognized as an insular endemic in 1877. Studies so far indicate that it is restricted to the contiguous islands of South and Middle Andamans. On these islands it apparently has a very localized distribution, giving rise to fears that it may be vulnerable and could face the threat of extinction with increasing developmental pressures on its habitat. Though it was reported to be extinct in 1993, its presence has since been documented and is currently protected by law in India. Nevertheless, nothing is known about the immature stages, its larval food plants or life history, and very little is known about its habitat and periods of occurrence on the islands. Here, details of all these aspects of this little-known butterfly of the Andaman Islands are presented. This should prove useful in the formulation of a conservation strategy for this iconic Oriental butterfly.

Cytoplasmic incompatibility as a means of controlling Culex pipiens quinquefasciatus mosquito in the islands of the south-western Indian Ocean

The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands.

Mosquitoes of the Culex pipiens complex are important vectors of human pathogens including filarial parasites and many currently expanding arboviruses. The absence of effective vaccines and the evolution of insecticide resistance stress the urgent need for the development of novel control strategies. One strategy that is receiving increasing attention is based upon the use of the intracellular bacteria Wolbachia, which induce a form of sterility known as cytoplasmic incompatibility in mosquitoes. Here, we show that a Wolbachia strain, named wPip(Is) and naturally infecting Cx. p. pipiens from Turkey, can be used in the Incompatible Insect Technique (IIT) to sterilize Cx. p. quinquefasciatus females from several islands of the southwestern Indian Ocean (SWIO). The wPip(Is) strain was introduced into SWIO Cx. p. quinquefasciatus nuclear background leading to the LR[wPip(Is)] line. Males from this latter line were found to sterilize all wild females tested, and no difference in mating competition was observed between LR[wPip(Is)] and wild males. These results encourage the development of an IIT program based on the wPip(Is) strain to control mosquito populations in the SWIO.

Genetic diversity, geographical range and origin of Bemisia tabaci (Hemiptera: Aleyrodidae) Indian Ocean Ms

The whitefly Bemisia tabaci is a pest vector of begomoviruses on crops worldwide. Bemisia tabaci is composed of a complex of cryptic species which barely interbreed. An exception is the Ms from the South West Indian Ocean (SWIO), which crosses in low proportions with the exotic B. The Ms, together with B and Q is part of the same phylogenetic clad. To infer the genetic structure, the geographical range and putative origin of this putative species, microsatellite data and mitochondrial DNA (cytochrome oxydase I) sequences were analysed on an extensive sample set, including all the islands of the region and samples from mainland Africa. Only B and Ms populations were detected across these islands. The exotic B was found only on the islands of Réunion and Mauritius, whereas the Ms is found on all the SWIO islands. Very high isolation by distance was found for the Ms populations between islands of the SWIO, suggesting a long period of presence in this region. Ms populations from mainland Africa had a higher COI diversity than the Ms of the SWIO islands. This diversity is correlated with size and geological ages of the SWIO islands. The population genetic data obtained are in accordance with an origin of Ms in Africa, followed by its expansion and evolution across the SWIO islands prior to human arrival, confirming the status of Ms as indigenous in the SWIO islands.

Antiplasmodial, anti-inflammatory and cytotoxic activities of various plant extracts from the Mascarene Archipelago

AIM OF THE STUDY

Antiplasmodial activity, inhibition of nitric oxide (NO) overproduction, and anti-proliferative activity were investigated in vitro to evaluate the bioactive potential of the traditional pharmacopoeia of the Mascarene Archipelago, which is known for its biodiversity and for the richness of its endemic flora.

MATERIALS AND METHODS

A total of 45 methanol (MeOH) and dichloromethane (DCM) extracts were prepared from 19 plant species collected on Réunion and Mauritius Islands. Ninety-six-well microplate assays were performed on chloroquine sensitive Plasmodium falciparum 3D7 strain, on LPS-stimulated Raw 264.7 murine macrophages and on A-549, DLD-1 and WS1 human cells. Activity was evaluated through spectrophotometric methods.

RESULTS

Activity was attributed to plant extracts expressing IC(50)<50μg/ml for antiplasmodial response, IC(50)<100μg/ml for cytotoxicity, and IC(50)<130μg/ml for anti-inflammatory reaction. The majority of the extracts tested (69%) exhibited potency in at least one of these three types of activity. This is the first report describing promising antiplasmodial activity (IC(50)<15μg/ml) for Psiadia dentata DCM extract and Terminalia bentzoe MeOH bark extract. NO inhibition assay revealed seven interesting plants, described for the first time as anti-inflammatory: Aphloia theiformis, Buddleja salviifolia, Eupatorium riparium, Hiptage benghalensis, Psiadia arguta, Psiadia dentata, and Scutia commersonii. Finally, anti-proliferative activity was observed for two endemic species, Geniostoma borbonicum and Nuxia verticillata.

CONCLUSION

Using the criterion of endemism as part of the criteria for traditional medicinal use raises the chances of finding original active principles. In our case, 86% of the endemic plants tested displayed pharmacological interest.

Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean

The Subantarctic Kerguelen Islands (49°S, 70°E) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g(-1) lipid, and dioxin-like PCB was 19 and 69 ng g(-1) lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels.

Better be prepared than sorry: what should the New Zealand healthcare system learn from the 2009 Pacific Tsunami?

On the early hours of the 29 September 2009, an earthquake in the Pacific generated a massive tsunami that caused significant destruction and claimed many lives across several Pacific nations. The disaster initiated an international relief operation from New Zealand (NZ), Australia, and the United States. The NZ healthcare response was adequate given the multiple challenges encountered. This article reviews the challenges faced by NZ healthcare responders to the Pacific Tsunami. Furthermore, it presents the lessons learnt from this operation in order to enhance the NZ healthcare system preparedness to respond to future disasters and mass emergencies nationally and internationally.

Pre- and post-1998 ENSO records of shallow-water octocorals (Alcyonacea) in the Chagos Archipelago

When compared, principal octocorals collected in the Chagos Archipelago before and after the 1998 ENSO shared many common taxa. While a few discontinuities in their biodiversity revealed subtle changes in more persistent genera (Lobophytum, Sarcophyton), some fast-growing "fugitive" genera (e.g. Cespitularia, Efflatounaria, Heteroxenia) disappeared after the ENSO-related coral bleaching. Such transient fugitives might thus be eliminated from soft coral communities on isolated reef systems, possibly in the long term, by events of this nature. The appearance of Carijoa riseii, a species often considered a fouling organism, even an invasive, may well be indicative of reef degradation during the ENSO event. The post-ENSO recovery manifested by this fauna nevertheless gives cause for hope for their survival in the face of climate change.

Chikungunya fever in two German tourists returning from the Maldives, September, 2009

This report describes the first isolation and molecular characterisation of a chikungunya virus from two German tourists who became ill after a visit to the Maldives in September 2009. The virus contained the E1 A226V mutation, shown to be responsible for an adaptation to the Asian tiger mosquito Aedes albopictus. The E1 coding sequence was identical to chikungunya virus isolates from Sri Lanka and showed three nt-mismatches to the only available E1 nt sequence from the Maldives.

Relevance of the Flexner Report to contemporary medical education in South Asia

A century after the publication of Medical Education in the United States and Canada: A Report to the Carnegie Foundation for the Advancement of Teaching (the Flexner Report), the quality of medical education in much of Asia is threatened by weak regulation, inadequate public funding, and explosive growth of private medical schools. Competition for students' fees and an ineffectual accreditation process have resulted in questionable admission practices, stagnant curricula, antiquated learning methods, and dubious assessment practices. The authors' purpose is to explore the relevance of Flexner's observations, as detailed in his report, to contemporary medical education in South Asia, to analyze the consequences of growth, and to recommend pragmatic changes. Major drivers for growth are the supply-demand mismatch for medical school positions, weak governmental regulation, private sector participation, and corruption. The consequences are urban-centric growth, shortage of qualified faculty, commercialization of postgraduate education, untenable assessment practices, emphasis on rote learning, and inadequate clinical exposure. Recommendations include strengthening accreditation standards and processes possibly by introducing regional or national student assessment, developing defensible student assessment systems, recognizing health profession education as a field of scholarship, and creating a tiered approach to faculty development in education. The relevance of Flexner's recommendations to the current status of medical education in South Asia is striking, in terms of both the progressive nature of his thinking in 1910 and the need to improve medical education in Asia today. In a highly connected world, the improvement of Asian medical education will have a global impact.

Formicidae of the Andaman and Nicobar islands (Indian Ocean: Bay of Bengal)

Ants on the Andaman and Nicobar Islands, India were surveyed. These collections doubled the number of ant species recorded from these islands (from 59 to 125). Records include five endemic species, but no endemic genera. The surveys were fairly superficial, and it is likely many species remain to be discovered on these islands.

Impact of Chikungunya virus infection on health status and quality of life: a retrospective cohort study

BACKGROUND

Persistent symptoms, mainly joint and muscular pain and depression, have been reported several months after Chikungunya virus (CHIKV) infection. Their frequency and their impact on quality of life have not been compared with those of an unexposed population. In the present study, we aimed to describe the frequency of prolonged clinical manifestations of CHIKV infection and to measure the impact on quality of life and health care consumption in comparison with that of an unexposed population, more than one year after infection.

METHODOLOGY/PRINCIPAL FINDINGS

In a retrospective cohort study, 199 subjects who had serologically confirmed CHIKV infection (CHIK+) were compared with 199 sero-negative subjects (CHIK-) matched for age, gender and area of residence in La Réunion Island. Following an average time of 17 months from the acute phase of infection, participants were interviewed by telephone about current symptoms, medical consumption during the last 12 months and quality of life assessed by the 12-items Short-Form Health Survey (SF-12) scale. At the time of study, 112 (56%) CHIK+ persons reported they were fully recovered. CHIK+ complained more frequently than CHIK- of arthralgia (relative risk = 1.9; 95% confidence interval: 1.6-2.2), myalgia (1.9; 1.5-2.3), fatigue (2.3; 1.8-3), depression (2.5; 1.5-4.1) and hair loss (3.8; 1.9-7.6). There was no significant difference between CHIK+ and CHIK- subjects regarding medical consumption in the past year. The mean (SD) score of the SF-12 Physical Component Summary was 46.4 (10.8) in CHIK+ versus 49.1 (9.3) in CHIK- (p = 0.04). There was no significant difference between the two groups for the Mental Component Summary.

CONCLUSIONS/SIGNIFICANCE

More than one year following the acute phase of infection, CHIK+ subjects reported more disabilities than those who were CHIK-. These persistent disabilities, however, have no significant influence on medical consumption, and the impact on quality of life is moderate.

Identifying reefs of hope and hopeful actions: contextualizing environmental, ecological, and social parameters to respond effectively to climate change

Priorities for conservation, management, and associated activities will differ based on the interplay between nearness of ecosystems to full recovery from a disturbance (pristineness), susceptibility to climate change (environmental susceptibility [ES]), and capacity of human communities to cope with and adapt to change (social adaptive capacity [AC]). We studied 24 human communities and adjacent coral reef ecosystems in 5 countries of the southwestern Indian Ocean. We used ecological measures of abundance and diversity of fishes and corals, estimated reef pristineness, and conducted socioeconomic household surveys to determine the AC of communities adjacent to selected coral reefs. We also used Web-based oceanographic and coral mortality data to predict each site's ES to climate warming. Coral reefs of Mauritius and eastern Madagascar had low ES and consequently were not predicted to be affected strongly by warm water, although these sites were differentiated by the AC of the human community. The higher AC in Mauritius may increase the chances for successful self-initiated recovery and protective management of reefs of this island. In contrast, Madagascar may require donor support to build AC as a prerequisite to preservation efforts. The Seychelles and Kenya had high ES, but their levels of AC and disturbance differed. The high AC in the Seychelles could be used to develop alternatives to dependence on coral reef resources and reduce the effects of climate change. Pristineness weighted toward measures of fish recovery was greatest for Kenya's marine protected areas; however, most protected areas in the region were far from pristine. Conservation priorities and actions with realistic chances for success require knowledge of where socioecological systems lie among the 3 axes of environment, ecology, and society.

Life stage-related differences in hardening and acclimation of thermal tolerance traits in the kelp fly, Paractora dreuxi (Diptera, Helcomyzidae)

It is widely appreciated that physiological tolerances differ between life stages. However, few studies have examined stage-related differences in acclimation and hardening. In addition, the behavioural responses involved in determining the form and extent of the short-term phenotypic response are rarely considered. Here, we investigate life stage differences in the acclimation and hardening responses of the survival of a standard heat shock (SHS) and standard low temperature (or cold) shock (SCS), and the crystallization temperature (or supercooling point, SCP) of adults and larvae of the sub-Antarctic kelp fly, Paractora dreuxi. These stages live in the same habitat, but differ substantially in their mobility and thus environmental temperatures experienced. Results showed that neither acclimation nor hardening affected the lower lethal limits in larvae or adults. Adults showed an increase in survival of upper lethal limits after low temperature acclimation, whilst larvae showed a consistent lack of response. The acclimationxhardening interaction significantly affected the SCP in adults, but no response to either acclimation or hardening was found in the larvae. This study further demonstrates the complexities of thermal tolerance responses in P. dreuxi.

Environmental implications for disaster preparedness: lessons learnt from the Indian Ocean Tsunami

The impact of disasters, whether natural or man-made, not only has human dimensions, but environmental ones as well. Environmental conditions may exacerbate the impact of a disaster, and vice versa, disasters tend to have an impact on the environment. Deforestation, forest management practices, or agriculture systems can worsen the negative environmental impacts of a storm or typhoon, leading to landslides, flooding, silting, and ground/surface water contamination. We have only now come to understand these cyclical causes and impacts and realize that taking care of our natural resources and managing them wisely not only assures that future generations will be able to live in sustainable ways, but also reduces the risks that natural and man-made hazards pose to people living today. Emphasizing and reinforcing the centrality of environmental concerns in disaster management has become a critical priority, requiring the sound management of natural resources as a tool to prevent disasters and lessen their impacts on people, their homes, and livelihoods. As the horrors of the Asian tsunami of December 2004 continue to be evaluated, and people in the region slowly attempt to build a semblance of normalcy, we have to look to the lessons learnt from the tsunami disaster as an opportunity to prepare ourselves better for future disasters. This article focuses on findings and lessons learnt on the environmental aspects of the tsunami, and its implications on disaster preparedness plans. This article essentially emphasizes the cyclical interrelations between environments and disasters, by studying the findings and assessments of the recent Indian Ocean earthquake and tsunami that struck on 26 December 2004. It specifically looks at four key affected countries--Maldives, Sri Lanka, Indonesia, and Thailand.

Impact of the earthquake and tsunami of December 26, 2004, on the groundwater regime at Neill Island (south Andaman)

The aquifer and groundwater regime has been affected by the earthquake and tsunami of December 26, 2004, particularly on the islands and coastal regions of India. The groundwater regime on many islands of Andaman and Nicobar islands, which is the only source of fresh water on the islands, has been found to be deteriorated. Detailed hydrogeological studies have been carried out at one of the tiny islands of Andaman, namely Neill Island, and results have been compared with prior observations. It has been found that the shell limestone aquifer at a few places has developed cracks due to the earthquake and these openings have allowed quick movement of seawater into the aquifer resulting into deterioration of groundwater quality. In the places where the aquifer is at sea level, the tsunami waves have caused seawater ingress. Most parts of the island which have hard mudstone as a base and where the aquifer lies much above sea level, did not show any change in groundwater regime.

Effects of an alien ant invasion on abundance, behavior, and reproductive success of endemic island birds

Biological invaders can reconfigure ecological networks in communities, which changes community structure, composition, and ecosystem function. We investigated whether impacts caused by the introduced yellow crazy ant (Anoplolepis gracilipes), a pantropical invader rapidly expanding its range, extend to higher-order consumers by comparing counts, behaviors, and nesting success of endemic forest birds in ant-invaded and uninvaded rainforest on Christmas Island (Indian Ocean). Point counts and direct behavioral observations showed that ant invasion altered abundances and behaviors of the bird species we examined: the Island Thrush (Turdus poliocephalus erythropleurus), Emerald Dove (Chalcophaps indica natalis), and Christmas Island White-eye (Zosterops natalis). The thrush, which frequents the forest floor, altered its foraging and reproductive behaviors in ant-invaded forest, where nest-site location changed, and nest success and juvenile counts were lower. Counts of the dove, which forages exclusively on the forest floor, were 9-14 times lower in ant-invaded forest. In contrast, counts and foraging success of the white-eye, a generalist feeder in the understory and canopy, were higher in ant-invaded forest, where mutualism between the ant and honeydew-secreting scale insects increased the abundance of scale-insect prey. These complex outcomes involved the interplay of direct interference by ants and altered resource availability and habitat structure caused indirectly by ant invasion. Ecological meltdown, rapidly unleashed by ant invasion, extended to these endemic forest birds and may affect key ecosystem processes, including seed dispersal.

Assessment of the ecological quality status of soft-bottoms in Reunion Island (tropical Southwest Indian Ocean) using AZTI marine biotic indices

The ability of the two synthetic marine biotic indices, AMBI and M-AMBI, to account for changes in the ecological quality of coastal soft bottoms of Reunion Island according to disturbances was assessed from macrobenthic samples collected in five sectors between 1994 and 2004. Samples were collected under non-perturbed conditions and at two sites subjected to heavy organic enrichment. Both indices are based on a classification of macrofauna into ecological groups (EG), and their transfer to tropical waters required some adaptations. These indices proved efficient in detecting a degradation of habitat quality. Their use resulted in the classification of all sites sampled between 1996 and 1998 as "good" or "high". M-AMBI nevertheless tended to result in the attribution of a slightly worse ecological quality status than AMBI. Together with an update of the EG species list for the Indian Ocean area, our results support the extension of both indices for the assessment of tropical soft bottoms.

Chikungunya virus-induced myopericarditis: toward an increase of dilated cardiomyopathy in countries with epidemics?

The acute stage of infection with chikungunya virus, which is characterized of fever, polyarthritis, and occasional rash, can be complicated by myocarditis, as reported in a 21-year-old woman. Persisting changes on cardiac magnetic resonance imaging one year after disease onset could lead to delayed myocardial damage. An unexpected delayed increase in dilated cardiomyopathy may be observed in countries affected by the outbreak of chikungunya virus disease during 2005-2007.

Chronic peritoneal dialysis in South Asia - challenges and future

Chronic peritoneal dialysis (PD), especially continuous ambulatory PD (CAPD), is being increasingly utilized in South Asian countries (population of 1.4 billion). There are divergent geopolitical and socioeconomic factors that influence the growth and expansion of CAPD in this region. The majority of the countries in South Asia are lacking in government healthcare system for reimbursing renal replacement therapy. The largest utilization of chronic PD is in India, with nearly 6500 patients on this treatment by the end of 2006. A large majority of patients are doing 2 L exchanges 3 times per day, using glucose-based dialysis solution manufactured in India. Chronic PD is not being utilized in Myanmar, Bhutan, or Seychelles. Affirmative action by the manufacturing industry, medical professionals, government policy makers, and nongovernmental organizations for reducing the cost of chronic PD will enable the growth and utilization of this life-saving therapy.

Begomovirus 'melting pot' in the south-west Indian Ocean islands: molecular diversity and evolution through recombination

During the last few decades, many virus species have emerged, often forming dynamic complexes within which viruses share common hosts and rampantly exchange genetic material through recombination. Begomovirus species complexes are common and represent serious agricultural threats. Characterization of species complex diversity has substantially contributed to our understanding of both begomovirus evolution, and the ecological and epidemiological processes involved in the emergence of new viral pathogens. To date, the only extensively studied emergent African begomovirus species complex is that responsible for cassava mosaic disease. Here we present a study of another emerging begomovirus species complex which is associated with serious disease outbreaks in bean, tobacco and tomato on the south-west Indian Ocean (SWIO) islands off the coast of Africa. On the basis of 14 new complete DNA-A sequences, we describe seven new island monopartite begomovirus species, suggesting the presence of an extraordinary diversity of begomovirus in the SWIO islands. Phylogenetic analyses of these sequences reveal a close relationship between monopartite and bipartite African begomoviruses, supporting the hypothesis that either bipartite African begomoviruses have captured B components from other bipartite viruses, or there have been multiple B-component losses amongst SWIO virus progenitors. Moreover, we present evidence that detectable recombination events amongst African, Mediterranean and SWIO begomoviruses, while substantially contributing to their diversity, have not occurred randomly throughout their genomes. We provide the first statistical support for three recombination hot-spots (V1/C3 interface, C1 centre and the entire IR) and two recombination cold-spots (the V2 and the third quarter of V1) in the genomes of begomoviruses.

Characterization of reemerging chikungunya virus

An unprecedented epidemic of chikungunya virus (CHIKV) infection recently started in countries of the Indian Ocean area, causing an acute and painful syndrome with strong fever, asthenia, skin rash, polyarthritis, and lethal cases of encephalitis. The basis for chikungunya disease and the tropism of CHIKV remain unknown. Here, we describe the replication characteristics of recent clinical CHIKV strains. Human epithelial and endothelial cells, primary fibroblasts and, to a lesser extent, monocyte-derived macrophages, were susceptible to infection and allowed viral production. In contrast, CHIKV did not replicate in lymphoid and monocytoid cell lines, primary lymphocytes and monocytes, or monocyte-derived dendritic cells. CHIKV replication was cytopathic and associated with an induction of apoptosis in infected cells. Chloroquine, bafilomycin-A1, and short hairpin RNAs against dynamin-2 inhibited viral production, indicating that viral entry occurs through pH-dependent endocytosis. CHIKV was highly sensitive to the antiviral activity of type I and II interferons. These results provide a general insight into the interaction between CHIKV and its mammalian host.

Chikungunya virus (CHIKV) is a reemerging alphavirus responsible for an unprecedented epidemic in countries of the Indian Ocean region, causing an acute and painful syndrome with strong fever, asthenia, skin rash, polyarthritis, and lethal cases of encephalitis. The most recent epidemic reemergences were documented in Kinshasa, (50,000 estimated cases in 1999–2000), in Indonesia (2001–2003), the Indian Ocean islands of Mayotte, Mauritius, Réunion, and the Seychelles (270,000 cases in 2005–2006 in La Réunion island), and in India (1.4 to 6.5 million estimated cases in 2006–2007). There is a critical lack of knowledge on the biology of CHIKV. In particular, virtually nothing is known about the interaction of CHIKV (and of most alpahaviruses) with human primary cells. We have studied the replication characteristics and the tropism of clinical CHIKV strains from La Réunion. We designed various assays and reagents to follow viral replication, and we report here that adherent cells (epithelial and endothelial cells, primary fibroblasts), as well as macrophages, are sensitive to infection. In contrast, blood cells did not allow viral replication. We also characterized viral entry pathways and sensitivity to interferons. These results provide a general insight into the interaction between CHIKV and its mammalian host. This paper is the result of a collaborative effort between numerous teams from Institut Pasteur, the Groupe Hospitalier Sud Réunion, and other institutions. Our aim was to establish a task force with multiple and complementary expertise on virology, immunology, and cell biology in order to characterize this enigmatic virus.