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PubMed1993

Human serum resistant promastigotes of Leishmania infantum in the midgut of Phlebotomus perniciosus.

Promastigotes of Leishmania infantum develop from early-stage normal human serum (nHS) sensitive forms to a partially nHS resistant stage in the midgut of Phlebotomus perniciosus. This development begins about day 7 after the sandfly has taken its initial infective bloodmeal. The onset of partial nHS-resistance occurs when mass proliferation of midgut promastigotes is already completed and the parasites have begun to differentiate into small, highly motile cells. In this parasite/vector interrelationship, the stomodeal valve seems to be a barrier which limits the development of L. infantum in P. perniciosus to the midgut.

Animals↗
PubMed1993

Population dynamics of Phlebotomus papatasi (Diptera:Phlebotomidae) in Pondicherry, India.

Investigations on the population dynamics of Phlebotomus papatasi were carried out. The average indoor resting density fluctuated between 16.70 and 2.25/man-hour in different seasons with a maximum density during monsoon season. There was a significant positive correlation between density and rainfall. Probability of daily survival of adult population was high in monsoon and low in summer. Both relative humidity and temperature influenced the survival. The finite rate of natural increase of the field population was maximum in October and minimum in April. The monsoon season, with moderate temperature and relative humidity was found to be favourable for the growth of P. papatasi population.

Animals↗
PubMed1996

The effect of immune sera from hamsters immunized with sandfly gut and whole body extract antigens on the fecundity and mortality of Phlebotomus duboscqi (Diptera: Psychodidae).

Phlebotomus duboscqi were fed on hamsters previously immunized with different concentrations of homogenized crude sandfly gut antigen and supernatant obtained from whole body extract. The humoral response in the rodents was quantified at different times post-immunization by the enzyme-linked immunosorbent assay. Sandflies were fed on either immunized or saline control hamsters and the effect of the blood meals on sandfly feeding, survival and fecundity was investigated. The humoral response in immunized hamsters as measured by the presence of P. duboscqi-specific IgG antibodies was significantly greater (P < 0.05) as compared to the controls. This difference was noted in sera collected on 15 and 25 days post-immunization. Sandflies fed on immunized hamsters had a significantly higher mortality (P < 0.05) and decreased egg production (P < 0.05) than those fed on unimmunized control hamsters.

Animals↗
PubMed1986

Leishmania major and L. donovani: effects on proteolytic enzymes of Phlebotomus papatasi (Diptera, Psychodidae).

Phlebotomus papatasi is susceptible to Leishmania major which it transmits in nature, but is resistant to L. donovani. The present study compares the effect of L. major and L. donovani on the proteolytic activity of P. papatasi gut enzymes. The experiments measured digestion of C14-labeled globin by gut homogenates of flies. Homogenates were prepared from flies fed on serum only (controls) or from flies fed serum containing promastigotes or their dried culture overlayer. In other experiments, the promastigotes or dried culture overlayers were added in vitro to the gut homogenate of control flies. Proteolytic activity of gut homogenate from flies infected with L. major was about one-third less than that of controls, while that from flies infected with L. donovani was one-third greater. Ingestion of L. major dried culture overlayer had an effect on flies similar to that of the promastigotes, while L. donovani dried culture overlayer produced no significant effect. When added to gut homogenate in vitro, promastigotes of both species promoted proteolysis as did dried culture overlayer of L. major. Dried culture overlayer of L. donovani, however, had an opposite effect. It is suggested that the observed reduction in proteolytic activity caused by L. major infection may result from inhibition of enzyme production.

Animals↗
PubMed1980

Fructose in wild-caught Phlebotomus ariasi and the possible relevance of sugars taken by sandflies to the transmission of leishmaniasis.

Cold, acidified anthrone was used to test 200 wild-caught sandflies (Phlebotomus ariasi females) for the presence of fructose. This sugar, or others with a fructose moiety, were demonstrable in 157 (79%) of the flies; proportions of flies positive in different tests ranged from 44 to 91%. Higher proportions of flies gave positive results when tested less than one hour after capture than when kept in the laboratory for more than 12 hours before testing. Similarly high percentages of flies were positive in samples collected coming to engorge on dogs and in those caught in CDC miniature light traps. These results, together with published reports of the demonstration of sugars in 25 individually tested sandflies of other species confirm that, like other biting flies, sugar is an important part of the diet of sandflies. Natural sugars may influence the development of leishmaniae in sandflies and their subsequent transmission. The anthrone test was found to be simple, rapid and suitable for field use; it is a valuable addition to indirect techniques for the study of the behaviour of sandflies.

Animals↗
PubMed1984

Cutaneous leishmaniasis in Kenya: transmission of Leishmania major to man by the bite of a naturally infected Phlebotomus duboscqi.

One leishmanial stock was isolated from a Phlebotomus duboscqi female captured in Baringo District, Kenya, and others from papular lesions that developed at sites where this sandfly had fed on a man. When characterized by cellulose acetate electrophoresis (eight enzymes examined), these isolates proved to be identical to known Leishmania major strains from man and a rodent (Arvicanthis sp.) and different from L. donovani and L. adleri, which also occur in Baringo. This is the first case of human cutaneous leishmaniasis caused by L. major reported from Kenya.

Electrophoresis, Cellulose Acetate↗
PubMed1985

Laboratory transmission of Leishmania infantum to Rattus rattus by the bite of experimentally infected Phlebotomus perniciosus.

The role of the sandfly species Phlebotomus perniciosus Parrot in laboratory transmission of Leishmania infantum was investigated. One of the wild reservoirs of the disease, the black rat (Rattus rattus), was used as vertebrate host. The parasite was transmitted by the bite of experimentally infected P. perniciosus to the black rat which, six months later, was infective to the same sandfly species. These experimental data confirm the role of P. perniciosus in the transmission of L. infantum, as suggested by earlier studies based on epidemiological data.

Animals↗
PubMed1985

Zoonotic cutaneous leishmaniasis in Saudi Arabia: the incrimination of Phlebotomus papatasi as the vector in the Al-Hassa oasis.

Surveys of the phlebotomine fauna in a focus of zoonotic cutaneous leishmaniasis (ZCL) in the Al-Hassa oasis, Eastern Province, Saudi Arabia, revealed only one species of Phlebotomus (P. papatasi) and three of Sergentomyia (S. antennata, S. clydei and S. fallax). 11 specimens of P. papatasi from six sites in the oasis were found with promastigotes in the midgut. An isolate from one of the sandflies was typed by the examination of isoenzymes and identified as Leishmania major, zymodeme LON-4 (= Montpellier zymodeme 26), the principal zymodeme of L. major isolated from patients with ZCL in the oasis. Three isolates from leishmanial lesions at sites of the bites of wild caught specimens of P. papatasi were also identified as the same zymodeme of L. major as the isolate from the sandfly. The findings show that P. papatasi is the vector of ZCL in the Al-Hassa oasis and probably in other ecologically similar foci in the Kingdom.

Animals↗
PubMed1986

Leishmaniasis in Sardinia: II. Natural infection of Phlebotomus perniciosus Newstead, 1911, by Leishmania infantum Nicolle, 1908, in the province of Cagliari.

Two promastigote-infected specimens of Phlebotomus perniciosus Newstead, 1911, were found in the province of Cagliari, Italy. The parasites from one specimen were successfully cultured in a hamster. The isolate was typed on 11 enzymes and shown to be identical with the reference strain of Leishmania infantum s.st. This is the first typing of a leishmanial organism from naturally infected P. perniciosus.

Animals↗
PubMed1986

Laboratory tests of three repellents against Phlebotomus perniciosus (Diptera:Psychodidae).

Three topical repellents were evaluated against Phlebotomus perniciosus using dose-response techniques. A total of 1800 laboratory reared nulliparous females of P. perniciosus, 2 to 15 days old, and 21 human volunteers were used. The effective dose (ED50 and ED90) for Deet, Indalone and MGK 11 has been determined. Indalone and MGK 11 were more effective than standard Deet. The data obtained indicate that P. perniciosus is highly sensitive to the repellents compared with other blood-sucking arthropods.

Adult↗
PubMed1987

Natural infection of Phlebotomus perfiliewi with Leishmania infantum in a cutaneous leishmaniasis focus of the Abruzzi region, Italy.

One out of 213 Phlebotomus perfiliewi caught from an endemic cutaneous leishmaniasis focus in Abruzzi region (Italy) was naturally infected with promastigotes. The parasites were grown in culture medium and in a hamster, typed by the examination of 11 isoenzymes, and found to be indistinguishable from Leishmania infantum s.st. (Montpellier zymodeme 1). The probable role of P. perfiliewi in the transmission of cutaneous leishmaniasis due to L. infantum s.l. in the focus is discussed.

Animals↗
PubMed1988

Isolation of Leishmania donovani from Phlebotomus martini in Baringo district, Kenya.

An 18-month sandfly survey was conducted at 4 locations in Baringo District, Rift Valley Province, Kenya. 3 collection techniques were used: aspiration, sticky paper trap, and light trap in sites selected because of their proximity to homes of visceral leishmaniasis patients diagnosed and treated within 6 months before the survey. Over 2000 female Phlebotomus martini were collected of which 6 females were found to have flagellate protozoan infections. 3 of these infections were cultured successfully and cryopreserved. 2 isolates were identified as Leishmania donovani by cellulose acetate electrophoresis. The zymogram of the third isolate was different from all Old World Leishmania reference strains examined, and it is still unidentified. The finding of 2 P. martini naturally infected with L. donovani strongly supports the hypothesis that this species is a vector of visceral leishmaniasis in this area.

Animals↗
PubMedDate not supplied

Experimental transmission of Leishmania major to vervet monkeys (Cercopithecus aethiops) by bites of Phlebotomus duboscqi (Diptera: Psychodidae).

Experimental transmission of Leishmania major to vervet monkeys (Cercopithecus aethiops) was accomplished by bites of Phlebotomus duboscqi sandflies. Three-day-old, laboratory-reared P. duboscqi were fed on leishmanial lesions on hamsters infected with L. major. The flies were re-fed on monkeys 10 d after infection. Five adult male vervet monkeys were used in concurrent transmission trials. Two of the monkeys received subcutaneous inoculations with stationary-phase promastigotes (2 x 10(6) promastigotes in 0.1 ml of medium) on the base of the tail. Putatively infected P. duboscqi were allowed to feed on the remaining 3 monkeys at sites on the base of the tail and on the right eyebrow. Challenges by sandfly bites resulted in multiple leishmanial lesions at all bite sites and, consequently, more lesion area than was produced by needle challenges. Post-feeding dissection of sandflies indicated that multiple lesions could be caused by bites of a single fly, and that probing alone, without imbibing blood, was sufficient for transmission. These first experimental transmissions of L. major to vervets by bites of P. duboscqi demonstrate that sandfly challenge is an efficient alternative to needle challenge, making available a unique Leishmania-sandfly-non-human primate model for use in vaccine development.

Animals↗
PubMedDate not supplied

Released glycoconjugate of indigenous Leishmania major enhances survival of a foreign L. major in Phlebotomus papatasi.

The effect of Leishmania glycoconjugate in the vector was investigated using Phlebotomus papatasi artificially infected with a Leishmania major strain that this vector does not transmit in nature. Glycoconjugate of the vector-specific strain of L. major was added to the infective meals of some fly groups and the success of infections with or without this substance was compared 4 d later. In the absence of glycoconjugate the parasites survived in 15.6% of the flies, while the addition of 0.5 mg/ml and 2 mg/ml raised the rate of infection to 34.3% and 63.0% respectively. Undigested blood was found in the stomach of 7.8% of the infected flies, whereas following meals with parasites and 2 mg/ml glycoconjugate it was present in 37% of the flies. The results demonstrated that this glycoconjugate increased the viability of the parasites in the unsuitable vector and delayed digestion of the infective meals. In a parallel experiment the glycoconjugate of L. donovani did not affect the survival of the parasites.

Animals↗
PubMedDate not supplied

The isolation of Leishmania major from Phlebotomus (Paraphlebotomus) caucasicus, in Isfahan province, Islamic Republic of Iran.

As part of a general survey of leishmaniasis and sandflies in the focus of zoonotic cutaneous leishmaniasis (ZCL) at Borkhar, a rural district north of the city of Isfahan, central Iran, Phlebotomus (Paraphlebotomus) caucasicus Marzinowsky from gerbil and jird burrows were found naturally infected with Leishmania major, zymodeme MON-26 (= LON-1). This is the first characterized isolate of L. major from a sandfly vector in Iran.

Animals↗
PubMedDate not supplied

Anthroponotic cutaneous leishmaniasis in Kabul, Afghanistan: the low susceptibility of Phlebotomus papatasi to Leishmania tropica.

Females of a laboratory colony of Phlebotomus papatasi from Kabul were fed through a membrane on a high dose of amastigotes of Leishmania tropica from the same place. Less than one-third of the flies became infected and only 6% developed heavy infections of the stomodaeal valve. From these observations, and previous studies by other workers, it is concluded that P. papatasi probably plays little or no part in the transmission of anthroponotic cutaneous leishmaniasis in Kabul. As in Saudi Arabia and Morocco, the most likely vector in Afghanistan is P. sergenti.

Animals↗
PubMed1988

RNA genome stability of Toscana virus during serial transovarial transmission in the sandfly Phlebotomus perniciosus.

We have carried out a T1 ribonuclease fingerprinting analysis of the RNA genomes of Toscana virus isolates from successive generations of an experimentally virus-infected laboratory colony of Phlebotomus perniciosus sandflies. This analysis detected no virus RNA genome changes during transovarial transmission of the virus over 12 sandfly generations (a period of almost 2 years). These results demonstrate that although RNA viruses can exhibit high rates of mutational change under a variety of conditions, Toscana virus RNA genomes can be maintained in a stable manner during repeated transovarial virus transmission in the natural insect host. The implications of these results for insect RNA virus evolution are discussed.

Animals↗
PubMed2005

First detection of Leishmania major in peridomestic Phlebotomus papatasi from Isfahan province, Iran: comparison of nested PCR of nuclear ITS ribosomal DNA and semi-nested PCR of minicircle kinetoplast DNA.

Two PCR methods were compared for their sensitivity in detecting cultured Leishmania major, before being used to estimate infection rates in female sandflies (Phlebotomus papatasi) collected from peridomestic animal shelters and the nearby burrows of the gerbil reservoir hosts, Rhombomys opimus, in Isfahan province, central Iran. A semi-nested PCR was used to amplify a fragment of minicircle kinetoplast (k) DNA with a length and sequence diagnostic for L. major, and a nested PCR was developed to amplify a fragment containing the internal transcribed spacers of the ribosomal RNA genes (ITS-rDNA) with a sequence diagnostic for L. major. The semi-nested PCR was less sensitive than the nested PCR when using DNA extracted from cultured promastigotes of L. major, but it was more sensitive for detecting L. major in wild-caught sandflies. At the edges of two Isfahan villages, infection rates were significantly higher in P.papatasi collected outside gerbil burrows (14/28) compared with those from peridomestic animal shelters (2/21). This is the first record of L. major detected in P.papatasi from peridomestic sites in Isfahan province.

Animals↗