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Potential climate driven changes in the epidemiology of human and animal disease are widely discussed and complex to assess. Recent spreads of exotic pathogens or vectors feed speculations; although most of these introductions are mainly linked to the increased worldwide traffic, trade of goods and transportation of animal and human, abiotic factors are known to impact on vectors and pathogens bionomics and their ability to establish in new ecosystems; altogether changes in climatic patterns and in seasonal conditions may affect disease behaviour in term of spread pattern, diffusion range, amplification and persistence in novel habitats. Invasion may result in the emergence of novel disease processes, presenting major challenges for the epidemiologists. In this paper, some of the ecological mechanisms underlying the impact of climatic change on disease transmission and disease spread are further described. Potential effects of different climatic variables on pathogens and hosts population dynamics and distributions are complex to assess and different approaches are used to describe the dynamics in ecological range and the availability of ecological niches for pathogens and vectors. However even when linkage between disease dynamics and climate change are relatively strong, there are always other factors also changing disease behaviour and these should be accounted for as well.

Three surveys on canine leishmaniasis were carried out in Cyprus (1993, 1998 and 1999) emphasise the presence of eleven species of phlebotomine sandflies: Phlebotomus (Phlebotomus) papatasi, P. (Paraphlebotomus) alexandri, P. (Pa.) jacusieli (first mention in Cyprus), P. (Pa.) sergenti, P. (Larroussius) galilaeus, P. (L.) tobbi, P. (Transphlebotomus) economidesi, P. (T.) mascittii, Sergentomyia (Sergentomyia) azizi (its specific statute is validated by the authors), S. (S.) fallax et S. (S.) minuta. P. (Adlerius) kyreniae was not caught during the surveys. The authors propose hypothesis of settlement of the island by phlebotomine sandflies according this species inventory. A first migration period took probably place during the Miocene time and a second one during the Pleistocene time.

During two surveys conducted in Cyprus (August 1998 and September 1999), 2,910 phlebotomine sandflies females were caught by CDC miniature light traps then dissected under binocular and examined on microscope. Eleven species were identified: Phlebotomus papatasi, P. sergenti, P. jacusieli, P. alexandri, P. tobbi, P. galilaeus, P. mascittii, P. economidesi, Sergentomyia fallax, S. minuta et S. azizi. The Larroussius species (P. galilaeus and P. tobbi) are the most abundant (more than 60% of our captures). Promastigotes were isolated from one specimen identified as P. tobbi. A Leishmania stock was successfully cultured and identified by isoenzyme characterisation as belonging to L. infantum zymodeme MON 1. The same zymodeme was isolated and identified from four dogs too. Because of the absence of usual vectors of L. infantum in the eastern part of the Mediterranean basin (P. neglectus and P. syriacus), and according to its distribution in Cyprus, P. tobbi constitute certainly a good local vector. It seems to be not very anthropophilic, that could explain the very few human cases.

Reports of a wide variation in space and time of the frequency of autogeny in Aedes (Ochlerotatus) detritus (Haliday, 1833) of the Camargue (Delta of the Rhône, Bouches-du-Rhône, Gard, France) led us to make an enzymatic analysis of male and female adults from different larval biotopes. The study showed the existence of two genetically distinct, sympatric populations which are morphologically indistinguishable. By diagnostic enzymes monomorph Got-2, Gpd, the grouping of the individual into two subgroups satisfies a Hardy-Weinberg equilibrium for the polymorphic enzymes. It is concluded that Ae. detritus is composed of a complex of two sibling species provisionally designated by the letters A (Got-2RR, GpdCC) and B (Got-2LL, GpdBB). In the present article, we retrace the history of the binomen Ae. detritus since the original description (sub nom. Culex detritus) to the split into the detritus complex. Certain ecophysiological (steno-eurygamy) and chorological (bioclimatic gradients N-S) criteria show that the sibling species B should be assigned to the taxon described in UK (Holywood, County Down, Ireland) by A.H. Haliday. Species A is here named Aedes (Ochlerotatus) Coluzzii n. sp.

The authors relate the realization, evaluation and eco-epidemiological applications of a "field-test": the agglutination of latex particles coated with a soluble antigen of Leishmania infantum in the presence of homologous antibodies. Evaluated on 1,035 canine sera, the sensitivity of the latex agglutination test (LAT) was 93.4% compared to the indirect fluorescent antibody test (IFAT). 90 node cultures were carried out on dogs with positive or negative LAT and/or positive or negative IFAT. The frequency of positive node cultures (70%) as versus positive LAT came between the results obtained for an IFAT > 1/40 (64%) and IFAT > 1/80 (73%). 32/33 (97%) dogs had positive node culture, LAT and IFIAT(> 1/80). 6 dogs had negative LAT but positive node culture: 5 of these had also an IFAT < 1/160. This test was used in the field on several eco-epidemiological surveys in leishmanian enzootic areas. Node cultures were made on the dogs with positive TL. 39 strains were isolated: 18 in Algeria, 15 in Morocco, 2 in Syria and 4 in Yemen. 13/39 strains were obtained from dogs with IFI < 1/160: 2 at 1/20, 8 at 1/40 and 3 at 1/80. In Algeria this test was also used for the diagnosis of human visceral leishmaniasis in a child. This quick, simple, sensitive and specific test could be usefully carried out on "field" surveys for the diagnosis of visceral-leishmaniasis in animals and human beings.

Phlebotomus mariae was first described in the South of Morocco in 1974. More specimens were found again recently in the High Atlas, showing that this species can be considered as a valid one, placed in the sub-genus Larroussius. The female remains to be found.

The authors report a case of Leishmania major leishmaniasis which occurred in a female kidney transplant recipient. In contrast with visceral leishmaniasis, disseminated cutaneous leishmaniasis seems to be exceptional in immunodepressed patients.

Out of 1,167 females of sandflies dissected, one specimen of Phlebotomus papatasi captured at a transmission site near Biskra, a well known Algerian focus of zoonotic cutaneous leishmaniasis, was found naturally infected with Leishmania major zymodeme MON-25. This supports classical observations of Sergent and al. P. papatasi as vector in this focus in 1921.

The causative agent of cutaneous leishmaniasis in Mauritania is identified for the first time as Leishmania major MON-117, a new zymodeme closely related to MON-26. The authors point out the need to study this previously unknown focus.

In an ecoepidemiological study in the Syrian foci of human visceral (VL) and cutaneous (CL) leishmaniasis, domestic dogs infected with Leishmania infantum MON-1 and L. tropica MON-76 were found for the first time. In Syria canine leishmaniasis caused by L. infantum, occurs in the humid and sub-humid western belt from the coastal zone to the nearby mountain ranges. Sporadis cases of human VL occur in this area. Canine CL, caused by L. tropica was found in the semi-arid zone in a village with a high human infection rate. The infection causes small papules or crusted ulcers on the nose or muzzle. These observations are relevant to control. In human VL foci it is recommended not to control the dog population, unless this is linked with other activities, such as rabies control. Control of dogs in the CL areas is not justified because of the small size of the lesions and the rarity of the parasites. Indeed the role of the dog as the "true" reservoir host is questionable. Human CL infection is best controlled by active case detection and specific treatment.

In response to an epidemic of oriental sore around Damascus, an ecological and epidemiological survey was carried out in the village of Dmeir, 40 km NE of Damascus. Parasites isolated from six cases from Dmeir, and two other cases from Syria were identified as Leishmania major, zymodeme MON-26. This zymodeme is known as the agent of zoonotic cutaneous leishmaniasis from the Sub-Saharian Sahel to the Near and Middle East. This is the first report of L. major in Syria. In a group of 234 school children aged 5-11 years, the leishmanin skin test was positive in 37%, indicating a high transmission rate. The epidemic seems to be the result of agricultural and industrial development projects in the area: numbers of both the gerbil reservoir host and sandfly vector appear to be increased by the land improvement.

In a Moroccan focus of cutaneous leishmaniasis caused by Leishmania tropica, 7,907 female sandflies captured with CDC traps were dissected from summer to autumn 1989. Among species of the genus Phlebotomus, only P. sergenti harbored promastigotes. Eighty-nine strains belonging to the complex L. tropica were isolated. The frequency of vector infection was zero in June, rose to 1.3% in August, and reached 9.9% in October, which indicates that the period of high risk is at the end of the hot season. Out of 89 strains isolated, 74 were completely typed and corresponded to the following four zymodemes: MON-102 (one strain), MON-107 (56 strains), MON-122 (two strains), and MON-123 (15 strains). Only the first two were observed in humans. The distribution of zymodemes MON-102 and MON-107 was very different in humans, dogs, and the vector. In one of the sites surveyed, which was strongly dominated by MON-107, the absence of human cases involving this zymodeme suggests the existence of a wild reservoir.

Ecoepidemiological analysis of a Moroccan focus of leishmaniasis caused by Leishmania tropica revealed considerable enzymatic diversity. Seven zymodemes belonging to the complex were identified in 149 strains isolated from humans, dogs, and the vector Phlebotomus sergenti. Three distinct subgroups were identifiable, two of which were in turn, composed of three "small variant" zymodemes. The diversity appears to be related to the age of the focus, which may have allowed colonization by zymodemes of different geographic origins. Diversification into "small variants" is apparently the result of recent mutation, possibly associated with genetic exchange.

A case of fatal visceral leishmaniasis due to a dermotropic strain of Leishmania infantum (Zymodeme MON-24) is related in an AIDS patient in spite of a specific treatment.

During an epidemiological survey of zoonotic cutaneous leishmaniasis in South-West Syria, Leishmania major zymodème MON-26 was isolated from a reservoir host, Psammomys obesus terraesanctae (Rodentia-Gerbillidae). The abundance of this rodent, its close contact with infected villages and the high prevalence of the infection (63,1%) indicate that this is the main reservoir host of oriental sore in the semi desert area of this country.

Cell fusion in Leishmania infantum and L. tropica was recorded by means of a camera and a video system. Promastigotes were obtained from cultures in both cases. Fusion began with attachment of the posterior extremities of two ovoid flagellates. Complete fusion, with disappearance of adjacent cell membranes took about five minutes. In parallel, the flagella appear larger and shorter. These observations support the hypothesis of genetic exchanges suggested by analysis of DNA and enzymatic proteins.

In anautogenous females of the Dipteran Culicidae Aedes detritus (Haliday, 1833), the neurosecretory products synthesized by the A cells of the pars intercerebralis are stored in the pericarya in absence of blood meal; on the contrary, in the autogenous females they are steadily released from emergency till the stages 3-4 of vitellogenesis; a slight storage occurs by the end of vitellogenesis. These facts suggest the important meaning of these cells in the regulation processes of vitellogenesis in Mosquitoes.

The presence of an anautogenous and stenogamic population of Culex pipiens pipiens in Languedoc, France, is reported. The anautogeny was confirmed through 10 generations. A Callot morphogram corresponded to the anautogenous form. These results raise again the question of the type of relationships, genetic or ecological, of the characters classically associated with autogeny.

An account is given of the fundamental methods used on an investigation of the canine enzootic of leshmaniasis in the Cévennes. The objective was to determine the relationship between the prevalence of infection on dogs and the density of the sandfly vector. The basis of the work was a phyto-ecological map of the two parameters. The results are of epidemiological interest as a logical approach which enable comparisons to be made between ecologically homogeneous sectors or strata. In each stratum the methods were carried out in two steps: the rural parishes were designated as statistical units, and were then examined for clusters composed of the dogs of each parish. Strata of small size were more exhaustively examined than the largest. The clustering techniques clearly revealed a heterogeneity in the distribution of canine leishmaniasis and villages in which non infections were found, were next to others where dogs were infected. The development of the enzootic was seen to be by an increase in the number of microfoci, rather than by a spread of the existing foxi. Finally the methods revealed a gradient in the morbidity of dogs from the cost to the highest points of the mountainrange. This gradient was strongly linked to the distribution and density of the vector, Phlebotomus ariasi.

The first case of oriental sore reported to Leishmania major is identified in Mali. The characterization of the stain isolated from a left arm lesion of a 30 years old european woman is carried out by electrophoretic analysis using enzymes, i.e. PGM, PGI, G-6-PDH, 6-PGDH, IDH, MDH, ME, GOT.

Out of 187 female Phlebotomus ariasi caught in the Cévennes focus of leishmaniasis 3 were found naturally infected with Leishmania. The infection in one of the three had spread from the midgut to the pharynx and proboscis. Stocks of Leishmania were isolated from two of the flies and 8 isoenzymes were examined. The newly isolated parasites were found to be indistinguishable from zymodeme 1 of Leishmania infantum s. st.

In the Cévennes, the distribution of canine leishmaniasis and, therefore, of human visceral leishmaniasis is usually on the middle slopes of hillsides. From previous work, it was assumed that the reason is that the same places are the preferred habitats of the sandfly vector, Phlebotomus ariasi Tonnoir, 1921. An investigation was made throughout one season (13.05.1977 to 7.10.1977) of the comparative densities of sandflies at different altitudes on two opposite sides of a selected hill (le massif d'Oiselette) in the department of Gard. Oiled papers, changed every 15 days, were distributed at 22 points at altitudes from 165 to 600 m above sea level. A total of 5,050 sandflies were collected and analysed according to altitude and time of year. Of the sandflies collected, 86,2% were P. ariasi, 0,3% were P. perniciosus Newstead, 1911, 0,1% were P. mascittii Grassi, 1908 and 13,4% were Sergentomyia minuta (Rondani, 1843). P. ariasi was present at all altitudes with maximum densities between 300 and 500 m. This species was present from mid May until late September, with a maximum density at the end of July. The results support the notion that, in the Cévennes, inhabitants of farms and villages on the slopes of hillsides at altitudes of 300-500 m are at the greatest risk of acquiring leishmaniasis because these places are the preferred habitat of the sandfly vector, P. ariasi.

The study of allozymic variations at four enzymatic loci (Est-2, alpha-Gpd, Got-1 and Got-2) in populations of Aedes detritus (Hal.) from 27 localities in Southern France has shown that this species is composed of two kinds of sympatric populations which do not interbreed in nature. Single specimens of Aedes detritus can be attributed to one or other type of population (sibling species) by the genotype at the alpha-Gpd or Got-2 loci (type A populations are homozygous for Got-2R allele and the frequency of the alpha-GpdC allele is higher than 98%; type B populations are homozygous for Got-2L allele and the frequency of the alpha-GpdB allele is higher than 98%). Moreover, allelic frequencies at the Est-2 and Got-1 loci are different in both types of populations. The fact that both kinds of populations coexist in the same pond shows that the isolating mechanism is not an adaptation to the larval environment, but rather involves mechanisms pecular to adults (precopulatory mechanism or interpopulation sterility).