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R Killick-Kendrick

Publications and source records attributed to R Killick-Kendrick.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Ecology of leishmaniasis in the south of France. 21. Influence of temperature on the development of Leishmania infantum Nicolle, 1908 in Phlebotomus ariasi Tonnoir, 1921. Experimental study].

The influence of temperature on the life-cycle of Leishmania infantum Nicolle, 1908 (isolated from a dog in the Cévennes) in a known vector (Phlebotomus ariasi Tonnoir, 1921) was studied with special reference to the proportion of flies infected and the intensity and localization of parasites in the sandfly. Wild female sandflies were caught at night by active searches and were put with a heavily infected dog in a mosquito net on the night of capture. On the following morning, engorged females were tubed individually and were then maintained at 10, 15, 20, or 25 degrees C (+/- 1.5 degrees). The temperatures were chosen after preliminary experiments which showed that temperatures of 30 degrees C or less than 5 degrees C were lethal to both the sandfly and, usually, the parasite. Midguts of the flies were dissected and examined 6 to 10 days after the infective feed. Although there were no obvious differences in the proportions of infected sandflies at different temperatures, a statistical analysis of the finding (chi 2 test) showed that raising the temperature: significantly increased the overall proportion of infected sandflies; speeded up the multiplication of promastigotes in the midgut; controlled the movement of parasites forwards into the thoracic midgut (from 15 degrees C); encouraged the attachment of the flagellates to the wall of the stomodaeal valve (from 20 degrees C). The use of an exponential model to deduce the size of the parasite population at the different temperatures led to the conclusion that the optimum temperature for L. infantum is in the region of 25 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

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PubMed1985

Some epidemiological consequences of the evolutionary fit between Leishmaniae and their phlebotomine vectors.

There is a more or less close fit between Leishmania species and their vectors with the proven vector of one parasite often unable to support the full development of another. This fit is presumably a result of coevolution of vector and parasite and it is notable that, if a Leishmania has different invertebrate hosts in different parts of its range, the vectors are often closely related. The epidemiological consequences of this restriction are, firstly, that the spread of the cutaneous leishmaniases of the Old World and, to a lesser degree, that of visceral leishmaniasis is restricted by the distribution of suitable vectors and, secondly, that secondary vectors are of less importance on the epidemiology of the leishmaniases than they are in malaria.

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PubMed1984

Parasitic protozoa of the blood of rodents. VI. Two new hemogregarines of the pygmy flying squirrel Idiurus macrotis (Rodentia: Theridomyomorpha: Anomaluridae) in West Africa.

Descriptions are given of two new species of Hepatozoon Miller, 1908 found in the pygmy squirrel, Idiurus macrotis, in the Ivory Coast. Gamonts of both are parasites of monocytes. The size and shape of the gamonts of one, H. normani n. sp., are similar to those of a number of gamonts of other species of rodent hemogregarines and the separate identity of the parasite is based on the host restriction of mammalian hemogregarines. The gamonts of the other species, H. dolichomorphon n. sp., are remarkably long and slender and are unlike those of any other known hemogregarine of mammals. Schizonts of this species were found in a smear prepared from heart blood.

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PubMed1984

A field comparison of seven diagnostic techniques for human trypanosomiasis in the Luangwa Valley, Zambia.

One serological and six parasitological techniques for diagnosing human trypanosomiasis were compared with regard to sensitivity, specificity, positive and negative predictive values, and practicality in field application in the Luangwa Valley of Zambia. Seven (0.64%) trypanosomiasis cases were diagnosed parasitologically in a survey of 1093 people from 19 villages. The indirect fluorescent antibody test (IFAT) was more sensitive but less specific than the parasitological techniques, detecting 71% of the confirmed cases in the first round of testing. Rat inoculation, the Giemsa stained thick film and miniature anion-exchange/centrifugation (mAEC) were all more sensitive than wet blood film examination, microhaematocrit centrifugation and wet film examination of the buffy coat after microhaematocrit centrifugation. The comparison indicated that the most effective, practical combination of techniques for survey in the Luangwa Valley was IFAT screening followed by examination of seropositive patients by rat inoculation and the mAEC (or stained thick film) in parallel format. Calculation of positive and negative predictive values showed that trypanosomiasis point prevalence measured in this way would still be underestimated by approximately 60%, indicating the need to improve IFAT specificity and parasitological sensitivity. Although only one of the seven patients diagnosed in the survey presented with signs and symptoms indicating possible trypanosomiasis, no evidence of a population of "healthy carriers" was found.

Adolescent↗
PubMed1984

[Ecology of leishmaniasis in Southern France. 18. Enzymatic identification of Leishmania infantum Nicolle, 1908, isolated from Phlebotomus ariasi Tonnoir, 1921, spontaneously infected in the Cévennes].

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.

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PubMed1984

Ecology of leishmaniasis in the south of France. 19. Determination of the hosts of Phlebotomus ariasi Tonnoir, 1921 in the Cévennes by bloodmeal analyses.

Engorged sandflies were collected using 58 CDC light traps set up nightly for 5 weeks at 12 stations in the commune of Roquedur, Gard, France, in the Cévennes focus of leishmaniasis. Of 782 engorged females, 593 were Phlebotomus ariasi, 3 were P. mascittii and 186 were not identified. Using the precipitin ring test and counter-current immuno-electrophoresis, the bloodmeals were tested with antisera to man, leporids, rodents, canids, mustelids, equids, suids, bovids, birds, lizards and amphibia. Of 530 identified bloodmeals, 2 were avian blood, 26 were mixed meals of mammalian blood and 25 were meals taken from unidentified mammals. Of the 477 other sandflies, 211 (44.2%) had fed on canids, 107 (22.4%) on man, 70 (14.7%) on bovids (presumed to be cattle at one station and goats elsewhere), 33 (6.9%) on leporids (probably mostly domesticated rabbits), 26 (5.5%) on mustelids (probably badgers), 17 (3.6%) on horses and 13 (2.7%) on rodents (probably brown rat). The proportions of feeds on different mammals varied according to their availability at each station. When both man and dog were equally available, the dog was preferred. The finding that, away from human habitation, P. ariasi commonly feeds on mustelids suggests the need for a reappraisal of animals of this family as possible reservoirs of leishmaniasis in the Cévennes.

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PubMed1984

Ecology of leishmaniasis in the south of France. 20. Dispersal of Phlebotomus ariasi Tonnoir, 1921 as a factor in the spread of visceral leishmaniasis in the Cévennes.

The dispersal of Phlebotomus ariasi was studied in mark-release-recapture experiments in the summer of 1980 in a valley on the north-eastern slopes of the Oiselette range in the Cévennes mountains, in the commune of Roquedur, Gard, 50 km north of Montpellier, France. More than 5,000 specimens of P. ariasi were marked with fluorescent powders and released in 9 batches at 3 different places. Seven batches were engorged females and two were unengorged females and males. From 1-29 days after release, 497 marked sandflies (approximately 9%) were recaptured by active searches with UV lamps or in 58 CDC light traps set up in groups of 4 or 5 at 12 recapture stations. Females released engorged generally remained within 250 m of the release point for the first eight days while the bloodmeal was being digested after which there was a tendency to disperse to distances greater than 350 m presumably in a search for oviposition sites or another bloodmeal. The furthest distance to which a female released engorged was shown to move was 925 m; it was caught 12 days after release. Some of the females released unfed quickly moved away from release points, sometimes to distances of 1,000 m or more. One of these was caught 68.5 hrs after release at a station 2,200 m from the release point. Male sandflies tended to stay near the point of release and were not recaptured at distances greater than 600 m. There was no evidence that the movement of the sandflies was assisted by wind. Observations on the dispersal of female sandflies confirm that leishmaniasis can be more widely spread than generally assumed by the movements of the vector.

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PubMed1982

Demonstration of hypnozoites in sporozoite-transmitted Plasmodium vivax infection.

Hypnozoites of two strains of the human relapsing malaria parasite, Plasmodium vivax, have been detected among maturing 7- and 10-day pre-erythrocytic schizonts in liver biopsies of chimpanzees infected by intravenous inoculation of sporozoites obtained from dissected salivary glands of heavily infected anopheline mosquitoes. As in the simian relapsing species, P. cynomolgi, the hypnozoites of P. vivax at 7 and 10 days are uninucleate forms of approximately 4-5 micrometers diameter, lying within the cytoplasm of individual hepatocytes. Their presence in this relapsing human species is added support for the hypnozoite theory of malarial relapse.

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PubMed1982

Observations on early and late post-sporozoite tissue stages in primate malaria. II. The hypnozoite of Plasmodium cynomolgi bastianellii from 3 to 105 days after infection, and detection of 36- to 40-hour pre-erythrocytic forms.

Confirmation of the existence of a persistent, uninucleate, dormant pre-erythrocytic stage, the hypnozoite, of the relapsing simian malaria parasite, Plasmodium cynomolgi bastianellii, has been obtained by means of experiments involving the intravenous injection into susceptible monkeys of 48 to 85 x 10(6) sporozoites derived from mosquitoes of a different species and source than employed previously. The development of these hypnozoites was traced from 3 days until 105 days after sporozoite inoculation, employing a sensitive immunofluorescence technique followed by restaining with Giemsa. From an average mean diameter of 4 micrometers at 3 and 5 days, uninucleate hypnozoites grow to 5 micrometers at 7 days, then persist with little change until at least 105 days after infection. Strong evidence for the viability of these persistent forms was obtained by treatment of a host monkey with primaquine, which eliminated all trace of hypnozoites present 2 weeks before. Examination of hepatic tissue from a monkey injected with sporozoites 36 and 40 hours earlier revealed rare uninucleate pre-erythrocytic forms of 2.5-micrometers diameter. These early forms were present in hepatocytes in a density only approximately 1/30th of that expected on the basis of numbers of pre-erythrocytic stages found in the same animal's liver 7 days after infection. Nevertheless, subinoculation experiments appeared to rule out the circulation as a vehicle for dissemination of any putative early intermediate hepatotropic forms from another site.

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PubMed1982

Observations on early and late post-sporozoite tissue stages in primate malaria. I. Discovery of a new latent form of Plasmodium cynomolgi (the hypnozoite), and failure to detect hepatic forms within the first 24 hours after infection.

Previous work in this laboratory has demonstrated the ability of the immunofluorescence technique to detect pre-erythrocytic stages of the primate malaria parasite, Plasmodium cynomolgi bastianellii, in hepatic tissue obtained as early as 48 hours after sporozoite inoculation. In an attempt to visualize still earlier post-sporozoite stages, hepatic tissue obtained from a rhesus monkey infected with 12,000,000 sporozoites was examined at 2, 12, 24, and 48 hours after inoculation, employing antisera reactive with both invertebrate and vertebrate stages of the parasite. Tissue was also obtained at 7, 50, 102, and 105 days after sporozoite inoculation, and was examined for adequacy of the hepatic infection and for the presence of late exoerythrocytic schizonts. Although a new, previously unrecognized, uninucleate latent stage of 5 micrometer diameter (the "hypnozoite") was detected among large maturing schizonts in the 7-day and later biopsies, no intrahepatic parasites were found in tissue taken at 24 hours or earlier, despite the presence of up to 61 7-day schizonts and eight hypnozoites per 5 X 8 mm section. Pre-erythrocytic forms again were detected at 48 hours, although in far smaller numbers than expected on the basis of the density of parasites at 7 days after infection. The significance of these observations is discussed in the context of previous negative findings.

Animals↗
PubMed1982

[Ecology of leishmaniasis in south France. 17. Sampling of Phlebotomus by the method of adhesive traps. Comparison with the technic of capture on human bait].

In the analysis of the ecology of foci of leishmaniasis in the South of France, a comparison was made of two methods of sampling the vector: the technique of oiled paper traps and of hand-catching off human bait. The techniques, used in parallel in a rural site (Cévennes) and in an urban site (built up areas in Marseilles) gave comparable results. In the Cévennes focus of visceral leishmaniasis, Phlebotomus ariasi Tonnoir, 1921 is the dominant sandfly; in the urban focus, it is replaced by Phlebotomus perniciosus Newstead, 1911. The analysis of captures shows that, in the South of France, in general, the method of sampling by oiled papers can be used instead of man-biting catches. The former method is easier and permits work over a wide area at many places simultaneously.

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PubMed1981

[Significance of enzymatic polymorphism in Leishmaniae--On three heterozygous stocks of Leishmania infantum Nicolle, 1908, Leishmania cf. tarentolae Wenyon, 1921 and Leishmania aethiopica Bray, Ashford and Bray, 1973 (author's transl)].

The analysis of 8 isoenzymes (PGM, PGI, G-6-PDH, 6-PGDH, IDH, MDH, ME, GOT)of 49 stocks of leishmaniae [35 of Leishmania infantum Nicolle, 1908, 10 of Leishmania cf. tarentolae Wenyon, 1921, 2 of Leishmania tropica (Wright, 1903) and 2 of Leishmania aethiopica Bray, Ashford and Bray, 1973] revealed heterozygous structures in three stocks. These structures were expressed by two (PGM) or three (PGI, 6-PGDH) spots on the electrophoretic gels. Two stocks were heterozygous for PGI alone [one of L. infantum from a dog in the Cévennes, France; one of presumed Leishmania tarentolae from Sergentomyia minuta (Rondani, 1843) from P. O., France] and one was heterozygous for PGI, PGM and 6-PGDH (L. aethiopica from man in Ethiopia). The results are comparable to those seen in eukaryotic organism with sexual reproduction and suggest that leishmaniae have diploid structures and a process of genetic exchange.

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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.

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