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Biomedical subjects

C Chastel

Publications and source records attributed to C Chastel.

242 records · Page 14Linked to original sources
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[Arbovirus infections in Tunisia: new serological survey of small wild mammals].

Sera of 103 small wild mammals (rodents, insectivora, cheiroptera) trapped at the beginning of 1980 in different areas of Tunisia were studied for antibody against 15 arboviruses. In inhibition haemagglutination tests, positive reactions were found against Dengue type 2 (2.2%), Tahyna (18.4%), Arumowot (42.7%) and Sicilian sandfly fever (31%) viruses. No antibody was found for 8 tick-borne viruses. In comparison with previous sero-surveys, our results indicated a fall of West Nile virus activity and the emergence of Tahyna virus. The possibility that wild cycles involving small mammals and the two phleboviruses may exist in Tunisia is discussed.

Animal Population Groups↗
PubMedDate not supplied

[Little savage mammalians: free-living amoebae vectors? (author's transl)].

We tried to prove the part of the little savage mammalians as active intermediate hosts to the intestine level for some free-living limax amoebae of limax group. For this we participated to several trapping-season in Britanny and in Tunisia. From 273 samplings, we studied 224 with the results thereafter: the rodents are the first (213/224) and the 3 most frequent species are also the most often hosts: 20/128 A. sylvaticus, 9/58 C. glareolus and 4/16 M. spretus. There must be a double positive factor: life in burrow near the earth and meal type. The 78 samplings for which we checked the free-living amoebae by stool examination, are the most poor by culture: 2/78 (2.5 p. 100). This lack explains the negative stool examination. The isolated amoebae belong for 31/34 to the genus Acanthamoeba, of one potentially pathogenic: A. hatchetti. Moreover the Finistere biotop appears particularly poor (2.5 p. 100 carriers in front of 21 p. 100 in Ille-et-Vilaine and 24 p. 100 in Tunisia).

Amoeba↗
PubMedDate not supplied

[Tick-borne arboviruses associated with marine birds; a general review (author's transl)].

About forty different arboviruses have been isolated from ticks associated with marine birds along all the coast of the world. The majority of these viruses belongs to 8 serogroups: Hughes, B, Kemerovo, Quaranfil, Nyamanini, Sakhalin, Unkuniemi and Upolu, while some others are non-grouped arboviruses. Two kinds of specialized ticks chiefly harbour these arboviruses: 1. The ticks of Ornitbodoros capensis complex from tropical, subtropical and temperate zones - 2. The ticks Ixodes uriae (= I. putus) and Ixodes signatus from subpolar, arctic and antarcitc zones and the surrounding temperate areas. All these ticks may attack humans, and severe pruritus and/or undifferenciated febrile illness may result. From a pathological point of view, some of these arboviruses, i.e. Soldado, Aride, Saumarez Reef, act as pathogens for marine birds inducing nest desertion and death or abnormal development of newly batched chicks. On the other hand, antibodies against other viruses, with well known or suspected epidemic potency, such as West Nile, Tyuleniy, Okhotskiy viruses, are currently found in human beings in certain coastal areas. These epidemiological data deserve further attention from concerned Health autorities.

Animals↗
PubMedDate not supplied

[Arbovirus infections in Spain: serological survey on small mammals].

Sera of 386 small mammals (rodents, insectivora, small carnivora and cheiroptera) trapped in Spain in 1978 and 1979 were studied for antibody against 10 arboviruses. Positive reactions were found against flaviviruses: West Nile (3.1%), dengue type 2 (0.5%), tick-borne encephalitis, European type (0.2%), together with Tahyna (6.5%), Uukuniemi (2%) and Bhanja (1%) viruses. The animal species concerned by positive reactions were essentially Mus spretus and Apodemus sylvaticus which were also the more numerous species trapped during the survey. In addition, in Crocidura russula, an unique reaction against West Nile virus was found. Results of our serosurvey in small mammals correlated well with those of previous reports in men or animals, from Portugal and from north-western Spain.

Animals↗
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[Ecology of Soldado virus: apparent lack of a viral inhibitor in th tissues of the vector tick Ornithodoros (Alectorobius) maritimus Vermeil and Marguet 1967].

It was previously postulated by others that suspensions of ticks O. (A.) maritmus may contain virucidal material (viral inhibitor) for Soldado virus leading to observe different infection rates according as the ticks were tested individually or in pools. In order to test this hypothesis, suspensions of nymphs of this species originating from a laboratory breeding stock, were mixed with Soldado virus before inoculation to suckling mice. No difference in mortality was observed between the mice receiving the virus exposed to tick suspensions and the controls. So, it seems unlike a viral inhibitor was responsible for the phenomenon. Other factors involved in Soldado virus ecology and possibly influencing the virus isolation efficiency are briefly discussed.

Animals↗
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Piperacillin-tazobactam treatment for severe intra-abdominal infections.

In this limited series of 23 patients suffering from severe or life-threatening intra-abdominal infection, piperacillin + tazobactam, together with adequate surgical drainage and resections, cured 78% of our patients and eradicated almost all the pathogens. Side effects included essentially eosinophilia and elevation of transaminases but was never severe. Piperacillin + tazobactam seem thus to be an acceptable treatment, associated with correct surgical drainage. This regimen has to be compared in appropriate trial versus gold standard therapy, such as imipenem, a beta-lactam with aminoglucoside and imidazole or clindamycin or with broad spectrum beta-lactam and other inhibitors or beta-lactamases, but our rate of cure is impressive in such a population.

Abdomen↗
PubMedDate not supplied

[Reflection on 2 current viral diseases: yellow fever and dengue].

Yellow fever and dengue are two current viral diseases induced by flaviviruses and usually transmitted by the same mosquito vector, Aedes aegypti. From 1987 to 1991, 18,753 cases of yellow fever, mainly from Africa, have been notified to WHO, leading to 4,522 deaths. On the other hand, WHO estimates that 2.5 billions individuals living in tropical areas are at risk to contract dengue fevers. In fact, 500,000 patients are hospitalized each year for dengue hemorrhagic fever/dengue shock syndrome and 90% of them are children. Nevertheless, the control of these two viral diseases would be reached easily in destroying mechanically the mosquito larval resting places. Although superficially similar, the two entities are in fact quite different. Relatively few is known about the pathogenesis of yellow fever whereas, for dengue fevers, it is difficult to integrate so many results accumulated to explain the occurrence of haemorrhagic phenomena according to the two main theories so far proposed which are not exclusive. The immunological one (S.B. Halstead) tries to explain the pathological events by the effect of anti-dengue enhancing antibodies acquired during a previous exposure to one of the dengue viruses, whereas that of increased virus virulence (L. Rosen) refers to fast passages between individuals during explosive epidemics.

Animals↗