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Madagascar has an important diversity of fleas (Siphonaptera), which almost species do not exist elsewhere. Scientists have provided huge efforts to improve knowledge on Malagasy fleas since the middle of 1900s particularly by investigating topics such as taxonomy, systematics, biogeography, and flea vector role. Since then, new species discovery has increased and currently, 48 species are recorded which the majority is endemic. Therefore, it becomes necessary to have updated keys to identify species membership. This paper presents morphological-based keys to identify at genus and species levels adult fleas reported as occurring in Madagascar. Illustrations are proposed to make easier the observation of morphological criteria, which may be tricky for sibling species., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America.All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Madagascar has been known for having bio-geo-ecological diversity which is reflected by a complex malaria epidemiology ranging from hyperendemic to malaria-free areas. Malaria-related attacks and infection are frequently recorded both in children and adults living in areas of low malaria transmission. To integrate this variability in the national malaria control policy, extensive epidemiological studies are required to up-date previous records and adjust strategies., Methods: A longitudinal malaria survey was conducted from July 1996 to June 2005 among an average cohort of 214 villagers in Saharevo, located at 900 m above the sea. Saharevo is a typical eastern foothill site at the junction between a costal wet tropical area (equatorial malaria pattern) and a drier high-altitude area (low malaria transmission)., Results: Passive and active malaria detection revealed that malaria transmission in Saharevo follows an abrupt seasonal variation. Interestingly, malaria was confirmed in 45% (1,271/2,794) of malaria-presumed fevers seen at the health centre. All four Plasmodia that infect humans were also found: Plasmodium falciparum; Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. Half of the malaria-presumed fevers could be confirmed over the season with the highest malaria transmission level, although less than a quarter in lower transmission time, highlighting the importance of diagnosis prior to treatment intake. P. falciparum malaria has been predominant (98%). The high prevalence of P. falciparum malaria affects more particularly under 10 years old children in both symptomatic and asymptomatic contexts. Children between two and four years of age experienced an average of 2.6 malaria attacks with P. falciparum per annum. Moreover, estimated incidence of P. falciparum malaria tends to show that half of the attacks (15 attacks) risk to occur during the first 10 years of life for a 60-year-old adult who would have experienced 32 malaria attacks., Conclusion: The incidence of malaria decreased slightly with age but remained important among children and adults in Saharevo. These results support that a premunition against malaria is slowly acquired until adolescence. However, this claims for a weak premunition among villagers in Saharevo and by extension in the whole eastern foothill area of Madagascar. While the Malagasy government turns towards malaria elimination plans nowadays, choices and expectations to up-date and adapt malaria control strategies in the foothill areas are discussed in this paper.

The Malaria Workshop organized by Institut Pasteur de Madagascar is an original course that applies innovative concepts to training of health professionals involved in malaria control in endemic countries. Course objectives are to enhance the skills needed to fight malaria (transversal competencies, critical approach, and position statement), to reinforce project cycle management proficiency, and to demonstrate how the Internet can be used as a source of documentation to compensate for geographical isolation. The Malaria Workshop is a six-consecutive-week full-day course that has been presented once a year since 2003. Seventy-six researchers, physicians or health ministry officials have already benefited from this training. Teaching methods emphasize andragogy that facilitates a learner/mentor relationship promoting exchange rather than transmission of knowledge and problem-based learning that engages learners to take an active part in gathering information. These methods in combination with the diverse backgrounds and experience of course participants foster a positive dynamic environment for learning that is monitored by weekly progress evaluation. Follow-up surveys have confirmed the positive effect of this training on the professional performance of former participants who become more involved in program development and fund-raising efforts. A professional network is growing and learners are starting to their experience. In this report workshop organizers describe the course's origins and concepts and present the conclusions drawn based on the first five yearly sessions.

Background: The highlands of Madagascar present an unstable transmission pattern of malaria. The population has no immunity, and the central highlands have been the sites of epidemics with particularly high fatality. The most recent epidemic occurred in the 1980s, and caused about 30,000 deaths. The fight against malaria epidemics in the highlands has been based on indoor insecticide spraying to control malaria vectors. Any preventive programme involving generalised cover in the highlands will require very substantial logistical support. We used multicriteria evaluation, by the method of weighted linear combination, as basis for improved targeting of actions by determining priority zones for intervention., Results: Image analysis and field validation showed the accuracy of mapping rice fields to be between 82.3% and 100%, and the Kappa coefficient was 0.86 to 0.99.A significant positive correlation was observed between the abundance of the vector Anopheles funestus and temperature; the correlation coefficient was 0.599 (p < 0.001). A significant negative correlation was observed between vector abundance and human population density: the correlation coefficient was -0.551 (p < 0.003). Factor weights were determined by pair-wise comparison and the consistency ratio was 0.04. Risk maps of the six study zones were obtained according to a gradient of risk. Nine of thirteen results of alert confirmed by the Epidemiological Surveillance Post were in concordance with the risk map., Conclusion: This study is particularly valuable for the management of vector control programmes, and particularly the reduction of the vector population with a view to preventing disease. The risk map obtained can be used to identify priority zones for the management of resources, and also help avoid systematic and generalised spraying throughout the highlands: such spraying is particularly difficult and expensive. The accuracy of the mapping, both as concerns time and space, is dependent on the availability of data. Continuous monitoring of malaria transmission factors must be undertaken to detect any changes. A regular case notification allows risk map to be verified. These actions should therefore be implemented so that risk maps can be satisfactorily assessed.

Re-emergence of human cases of plague after decades of silence does not necessarily mean that plague foci are re-emerging. Most often, Yersinia pestis bacteria have been maintained and circulating at low levels in the rodent populations. It seems therefore more appropriate to speak in terms of expansion or regression phases for sylvatic rodent plague foci and to reserve the term re-emergence for human cases. From the analysis of well-documented human plague cases in Madagascar, we underline the causes of re-emergence that can be generalized to most world foci, and can help define environments at risk where the threat of new emergence lurks. In all recent plague outbreaks, usually more than one risk factor was at the origin of the re-emergence. The reduction or discontinuance of surveillance and control, as well as poverty and insalubrity are the main factors in the re-emergence of human cases, allowing increased contacts with infected rodents and fleas. Environment changes (i.e. climatic changes, deforestation, urbanization) induce changes in flea and rodent populations by (i) extension of rodent habitats (for example by replacing forests by steppes or farmlands); (ii) modifications in population dynamics (possible outbreaks due to an increase of available food resources); but also, (iii) emergence of new vectors, reservoirs and new Y. pestis genotypes. Numerous and spontaneous genomic rearrangements occur at high frequencies in Y. pestis, which may confer selective advantages, enhancing the ability of Y. pestis to survive, to be transmitted to new hosts, and to colonize new environments. Therefore, any environmental change should be taken as a warning signal and active surveillance programs should be initiated.

The males of three new and rare species of the Malagasy endemic genus Paractenopsyllus Wagner, 1938 are described. Paractenopsyllus beaucournui, P. oconnori and P. raxworthyi have been collected on endemic small mammals and the black rat. As for others species of the genus, biotopes are rain-forests of the central highlands or the northern mountains of Madagascar. Two of the described species were collected at elevations lower than typical for the genus and below the limits of the highland bioclimatic zone. Morphological affinities between these new species and those already described provide taxonomic framework for the genus. An updated identification key is provided for the diagnosis of all the 20 Malagasy species of Leptopsyllinae.

Five new species of the malagasy endemic genus Paractenopsyllus Wagner, 1938, are described. Paractenopsyllus rouxi, P. ratovonjatoi, P. duplantieri, P. juliamarinus and P. gemelli have been collected on endemic small mammals and the black rat. Biotopes are mid-elevation rain-forests of the central highlands or the northern mountains of Madagascar. Morphological affinities between these new species and those already known provide taxonomic links within the genus. Differences in the spatial and altitudinal distributions and host ranges allow discussion of the potential factors important in the species distribution of this genus.

A 4-year entomological study was carried out in Southern Madagascar to identify malaria vectors, evaluate the transmission and compare the influence of irrigation in the sub-arid and adjacent humid regions. Three villages were involved in this entomological survey: Androvasoa (located in the natural sub-arid ecosystem), Pépiniére (sited at the centre of an irrigated rice scheme in the sub-arid region) and Esana (bordered with rice fields in the humid region). Mosquitoes were collected inside and outside dwellings when landing on human beings, with light traps and with knockdown indoor sprays. Anopheles arabiensis, Anopheles merus and Anopheles funestus were found in every village while Anopheles gambiae s.s. was only found in the village bordering the rice-fields (Pépiniére) and Anopheles mascarensis, a mosquito native to Madagascar, was only found in the humid region (Esana). In Pépiniére, the annual entomological inoculation rate (EIR) was low (EIR=0.4 infective bites/man/year (IBM)). In the irrigated scheme of the sub-arid region, malaria transmission was 150 times higher (mean EIR=63 IBM) than in the natural ecosystem and A. funestus was the main vector, responsible for 90% of infective bites. In Esana, the level of malaria transmission was high (EIR=41 IBM) and 2/3 of the infective bites were due to A. mascarensis, despite the presence of A. gambiae s.s. and A. funestus. These results are discussed with reference to the impact of irrigation on malaria in Africa ("the paddies paradox").

Following considerable sampling in Malagasy forests, two new species of endemic fleas from Madagascar are described. These are T. rodhaini n. sp. and P. goodmani n. sp., collected on small mammals. The material of T. rodhaini allows us to describe the previously unknown female of the genus Tsaractenus. We also complete the initial description of the genus with new diagnostic characters. Although it belongs to Paractenopsyllus, P. goodmani shows many unique characteristics. To help resolve certain systematic issues involving Malagasy Leptopsyllinae we introduce the new subgenus Consobrinopsyllus of Paractenopsyllus for P. goodmani. Its particular condition makes us consider valuable characters of the genus Tsaractenus. Carrying several traits of this genus, P. goodmani could constitute an intermediate step between the two endemic Malagasy leptopsylline genera. Considering these new findings the actual taxonomic position of the Malagasy genera among the Leptopsyllinae is discussed.

A method associating an anticoagulant rodenticide and an insecticide called Kartman bait-box aimed both at fighting reservoir and vectors of plague. It was evaluated in two neighbourhoods of Antananarivo (Madagascar) from October 2002 to May 2003. It involved the local community in the control. The study was carried out in Ambodirano-Ampefiloha refered as treated neighbourhood in which the Kartman bait box were laid out with an anticoagulant rodenticide and an insecticide with a rapid action versus a "pilot neighbourhood", Ankorondrano-Andranomahery in which the boxes were provided with non poisoning bait and non insecticidal white powder. The rodenticide used was Baraki (difethialone 25 ppm) and the insecticide was a powder of Propoxur 3%. The evaluation of effectiveness of this method was based on the four following parameters: (1) the number of dead rats collected daily inside and in the vicinity of the houses, (2) the daily number of baits non consumed in the Kartman bait box, (3) the cheopis index of the rats trapped using the BTS trap, and (4) the flea carrier index of the rats captured monthly with BTS trap. The cheopis index and the flea carrier index of the rats were calculated monthly. The number of rats that died in the treated neighbourhood was of 968 versus 3 in the pilot neighbourhood. The other parameters reached a stable level after 3 months. Between days 120 and 180, the mean number of unconsumed baits was 2.79 in the treated neighbourhood versus 0.14 in the pilot neighbourhood, the flea carriage (percentage of parasitized hosts) was 0% versus 61% in the pilot neighbourhood, and the cheopis index was 0.0 versus 5.0 in the pilot neighbourhood. This study demonstrates that Kartman bait-boxes reached the rat borne and the vectors of plague found in urban area. We propose to use this method extensively both during epidemic and inter-epidemic contexts.

Anopheles mascarensis has been demonstrated to be a vector of human malaria in the East coast of Madagascar. Here, we present original data obtained from 1996 to 2003 on the distribution, biology and vectorial capacity of An. mascarensis in the Middle-West of Madagascar. This species is consistently exophilic both for its trophic and resting behaviour. This accounts for the absence of clear impact of any indoor insecticide spraying. This species is mainly zoophilic, but can occasionally bite humans, which explains a low sporozoitic index (1/2218 = 0.045%). The densities of human landing mosquitoes are most of the time very low, with the exception of a peak between May and August at the beginning of the dry season. It implies that the vector's efficiency is very low but not insignificant in the Middle-West of Madagascar, a situation opposite to what is observed on the East coast. The vectorial efficiency of An. mascarensis and An. arabiensis would enable to maintain a low malarial endemicity in the Middle-West, even in the complete absence of An. funestus.

Chloroquine has been used in Madagascar since 1945 and remains the first-line treatment for uncomplicated cases of malaria. Low-grades of resistance type R1 and R2 have been reported. Thus, in vitro tests were performed in order to monitor the drug sensitivity of Plasmodium falciparum from different study sites, with the aim of identifying alternatives to chloroquine. Chloroquine IC50 values ranged from 0.2 nM to 283.4 nM (n = 190, mean IC50 = 52.6 nM; 95% CI = 46.1-59.1 nM). Fifteen isolates (7.9%) were chloroquine-resistant. One mefloquine-resistant isolate was detected (1/139). The test isolates were sensitive to amodiaquine (n = 118), quinine (n = 212), pyrimethamine (n = 86) and cycloguanil (n = 79). The median IC50 for amodiaquine was 12.3 nM (mean IC50 = 15.3 nM, 95% CI = 13.3-17.3 nM). Amodiaquine was 3.4 times as active as chloroquine in vitro and 7 times as active as quinine against P. falciparum. These results indicate that amodiaquine may be a potent alternative to chloroquine in Madagascar. There was positive correlation between tested quinoline-containing drugs activities, which suggests in vitro cross-susceptibility.

The genus Coquilletidia includes some of the mosquitoes involved in the transmission of numerous arbovirosis. Adults are locally abundant and very aggressive for men. In Madagascar, thus genus concerns 3 species among which 2 are endemic and had not been described at larval stage this far. The authors describe a single larva of Coquilletidia collected at Ankazobe in the Middle West of Madagascar, at an altitude of 1200 meters. The geographical distribution of Coquilletidia adults collected in various bio-climatic zones in Madagascar, combined with observed morphological characters, permit us to attribute this larva to Cq. grandidieri.

Madagascar is a tropical island affected by many natural disasters. The eastern coastal zone--an area of perennial malaria transmission--is regularly exposed to cyclones. Few malaria studies have been done in this area of Madagascar, and none have examined the potential relationship between malaria and natural disasters. A mobile team spent six weeks in the fields doing three lines of research: an entomological study by catching mosquitoes and determining their species: a therapeutic study of chloroquine (CQ) and sulphadoxine-pyrimethamine (SP) according to a 14 days WHO protocol and also a study of physician's diagnostic ability. Physicians were asked to make a presumptive clinical diagnosis of all febrile patients, and these results were compared to those obtained from blood smear examinations. The entomological study found three major vectors species: Anopheles gambiae, An. funestus and An. mascarensis. The therapeutic study showed that SP was 100% effective (n = 13) and only one case of CQ treatment failure was recorded (1/15). Finally the diagnostic study demonstrated that presumptive diagnosis of malaria based on the only clinical signs leads to an over-estimation of malaria frequency. Over 68% (102/149) of febrile patients were diagnosed by physicians to have malaria while only 52 (34.9%) were proven positive. Of the 47 patients diagnosed clinically as malaria-negative, 12 (25.5%) turned out to be positive. Outbreaks of malaria during or after natural disasters in Madagascar can be successfully treated with either CQ or SP, but compliance may be better with SP since it requires only one dose. Perhaps equally important in the context of natural disasters is to have the capacity to make a definitive diagnosis, and the dipsticks should be made available.

This study aims to evaluate the prevalence and density of haemoparasites in native Malagasy birds. Among the 387 birds, belonging to 43 species sampled at six localities in different bio-climatic zones of the island, 139 (35.9%) showed at least 1 hemoparasite with, by order of frequency, Plasmodium and/or Haemoproteus (19.9%), microfilariae (13.7% of 387 birds), Leucocytozoon (11.1%) and Trypanosoma (1.0%). An analysis to further elucidate these observations took into account the interaction of different environmental variables (altitude, season, site of collection) or aspects of the birds (age, weight, sex). There is evidence that some parasites preferentially infect some bird species or families. The largest male birds harboured the highest prevalences and densities of haemoparasite, regardless of species. These findings extend knowledge of bird/blood parasite relationships of Malagasy birds and provide interesting insights, especially concerning the pathogenicity of this type of parasitism and the parasite transmission by insect vectors.

Starch gel electrophoresis was used to assess the polymorphism of 7 isoenzymes in single mosquitoes (field-collected F0 or F1 generation) for Aedes albopictus (8 strains) from northern Madagascar. Mosquitoes of the F2 generation (3 strains of Aedes aegypti and 10 strains of Ae. albopictus) were tested for oral susceptibility to dengue type 2 virus. Aedes aegypti was less susceptible to viral infection than Ae. albopictus. The genetic differentiation was less high between Ae. albopictus populations collected in agglomerations connected by highly frequented roads, indicating that human ground transportation favors mosquito dispersal. These results have implications for the ecology, pattern of migration, and relative importance in epidemic transmission of dengue viruses between the 2 Aedes species.

Between the 20th October and the 18th November 1998, an outbreak of bubonic plague was declared in a hamlet in the Ikongo district of Madagascar. We conducted an epidemiological survey because of the re-emergence of the disease in this area (the last cases had been notified in 1965) and because of the low altitude compared to the classical Malagasy foci. The outbreak had been preceded by an important rat epizootics during September. A total of 21 cases were registered with an attack rate of 16.7% (21/126) and a lethality rate of 33% (7/21). The disease was more prevalent in males (66% of cases) and children aged < 15 years, as observed in general throughout the country. The anti-F1 seroprevalence among the contact population was 13.5% (13/96), probably attributable to subclinical infection by Yersinia pestis. No rodent was trapped during the survey, but an endemic hedgehog (Tenrec ecaudatus) was highly seropositive, suggesting a recent transmission of the plague bacillus among this species. The small mammals and vectors possibly involved in these new foci were investigated in May 1999.

Our survey of mammals and fleas arose as a result of an outbreak of bubonic plague at an usually low altitude in the Ikongo district (Madagascar), while a previous study had found anti-F1 antibodies in an endemic hedgehog. Animals were sampled with live traps in two hamlets (Antanambao-Vohidrotra, 540 m alt. and Ambalagoavy, 265 m alt.) and with pitfall traps in a neighbouring forest (750 m alt.). Rat fleas were collected by brushing the fur and free-living fleas by use of light traps. The introduced shrew Suncus murinus was found only in the village of Ambalagoavy while the black rat (Rattus rattus) was found in all three sites and the only seropositive rat was caught at Antanambao-Vohidrotra. In contrast, among the Tenrecidae (endemic shrews and hedgehogs) found in the forest near the first village, four animals were found seropositive for anti-F1 antibodies. One of them was carrying the endemic flea Paractenopsyllus pauliani, not yet reported as a vector of plague. The endemic vector of plague, Synopsyllus fonquerniei, was found only in the first village of Antanambao-Vohidrotra, and the cosmopolite flea Xenopsylla cheopis only in Ambalagoavy. Although no Yersinia pestis could be isolated and no F1-antigen could be detected in these animals, we found evidence of the recent transmission of plague in Antanambao-Vohidrotra and the nearby forest, but not in Ambalagoavy. These data corroborate with the sylvatic plague cycle hypothesis in Madagascar and its involvement in the outcome of the bubonic plague outbreak in this district.

Ticks are traditionally considered being host-specific parasites. The pattern of tick-host relationship was elucidated by exhaustive collection from a considerable number of potential hosts from numerous sites in the Malagasy mid-altitude forest. It can from the findings be concluded that the Malagasy ticks found on small mammals may be distinguished as either having a broad host-specificity or being highly host-specific. The results may provide important information in respect to phylogenetic studies with regards to the geological history of Madagascar and its endemic fauna.

The effect of two different insecticides on flea control was tested from January to March 2000 in the Ivory village and the Ambatolahy village: Knox-Out, a microcapsulated formulation of diazinon, organophosphorous compound (240 gr/L) and the deltamethrin powder (2 g/kg ai), respectively. The villages are located 2.5 km apart in the Betafo region in Madagascar. Deltamethrin is a pyrethroid and is still used in the National Plague Control Program, whereas diazinon has not previously been applied in plague control in Madagascar. The flea index and the prevalence of rats carrying fleas in the two villages before and after (at one and two months follow-up, respectively) were measured to evaluate the effect of each insecticide. Flea index decreased significantly in both villages by at the first month follow-up. However, at the second month follow-up no significant differences in comparison to pre-treatment index values were observed in any of the villages. This study has demonstrated a similar immediate effect of deltamethrin and of diazinon, and confirmed the absence of remanent action of the two insecticides.

Following the severe malaria outbreak in the central highlands in Madagascar in 1986, a vector control program by use DDT pm 75 house-spraying has been implemented to operate in areas located at altitudes between 1000 and 1500 m. Early treatment with chloroquine has also been incorporated in the control program. To detect areas at particular high risk for malaria outbreak the Geographic Information System (GIS) has been applied and tested. The study has shown that the system can be used in malaria surveillance in order to identify areas in which an intense distribution of Anopheles funestus can be anticipated and, hence, targeted in spraying campaigns. The system may also be used to monitor changes in anti-malarial drug resistance, in addition, to control of other vector-born diseases.

The resistance of Xenopsylla cheopis from urban area to pyrethroids, to DDT, and their susceptibility to carbamate are known. We have evaluated the susceptibility of X. cheopis collected from three rural localities: Ambodisiarivo (district of Antananarivo Avaradrano), Mandoto (district of Betafo), Analaroa (district of Anjozorobe) in the province of Antananarivo and in Besoa (district of Ambalavao) in the province of Fianarantsoa. The standard WHO protocol was used and four insecticides were tested: deltamethrin 0.025%, cyfluthrin 0.15% (pyrethroids), DDT 4% (organochlorine), propoxur 1% and bendiocarb 0.1% (carbamate). X. cheopis has been shown resistance to DDT 4%, to deltamethrin 0.025% but was susceptible in the rural area around Antananarivo City. They were tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1% in the districts of Betafo and Anjozorobe. In Besoa, X. cheopis was resistant to DDT 4%, tolerant to deltamethrin 0.025% and cyfluthrin 0.15% but susceptible to propoxur 0.1% and bendiocarbe 1%. These results indicate that DDT and pyrethroids can not be recommended any more for the vector control in the rural area around the capital. The use of pyrethroids in the other districts of the central highland must be joined with a X. cheopis susceptibility control. In case of resistance to pyrethroids, carbamates would be proposed to control plague vector in the rural area. The high level of resistance to DDT and pyrethroid in the rural area around the capital confirms the importance of studying the flea population in different area of Madagascar and the possibility of the gene resistance propagation.

After a thirty year period of successful control, bubonic plague showed the first signs of return in Madagascar where a fatal outbreak occurred in Antananarivo in 1978. A second outbreak was observed in Mahajanga in 1991 after more than a half century. In 1997, 459 confirmed or presumptive cases were reported, as compared to 150 to 250 cases during the last years. However the actual extent of this recrudescence must be placed in the perspective of a more efficient control program that has led to better reporting of suspected cases and availability of more accurate diagnostic techniques. Recent research has led to the development of highly effective immunological diagnostic tools (detection of antibodies and F1 antigen) allowing not only better surveillance of the disease in man and animals but also renewed study of the epidemiological cycle in the current environment. In this regard the capacity of several endemic fleas as vectors and the role of the rat Rattus norvegicus and the musk shrew Suncus murinus are currently under investigation. Genetic study of strains collected from 1936 to 1996 has demonstrated the appearance of 3 new ribotypes of Yersinia pestis since 1982 in the zones of strongest plague activity in Madagascar. A strain showing multiresistance to standard therapeutic antibiotic agents was isolated in 1995. Bubonic plaque is a priority health problem in Madagascar but remains a major concern for the rest of the world.