[Statins and anesthesia: dilemma or obviousness? Is there still room for withdrawal of chronic statin therapy before surgery?]. / Statines et anesthésie: dilemme ou évidence? Faut-il arrêter ou poursuivre le traitement par statines avant une intervention chirurgicale?

Due to their action on the low-density lipoprotein-cholesterol (LDL-Cholesterol), statins efficiently take part in the treatment of coronary artery disease (CAD). Moreover, they exert various effects (called "pleiotropic") independently of their lipid lowering actions. All of these effects interact with inflammation, thrombosis and vasoconstriction during the perioperative period. However, statins may also increase the risk of rhabdomyolysis, a rare but potentially lethal complication. In this article, we will describe the advantages and disadvantages of statin therapy during the perioperative period. Although in the past, withdrawal of statins was recommended before anesthesia, there is now evidence that statins must be continued or even must be introduced before surgery. We will try to identify relevant situations were statins are still under-prescribed before surgery.

Entomological investigations in Chichaoua: an emerging epidemic focus of cutaneous leishmaniasis in Morocco.

Cutaneous leishmaniasis due to Leishmania tropica Wright seems to be an emerging disease in Chichaoua, a province located in southwestern Morocco. In this study, sand flies (Diptera: Psychodidae) were collected from 12 stations. Sticky traps were placed in domestic, peridomestic, and sylvatic sites. In total, 3,787 specimens consisting of 10 species (seven Phlebotomus and three Sergentomiya) were identified. Phlebotomus perniciosus Newstead, the predominant species, was abundant, especially in mountainous areas. Phlebotomus sergenti Parrot (12%) was found in all studied villages where it was associated with domestic and peridomestic habitats. On the basis of its abundance, distribution, and notable anthropophily, P. sergenti, a proven vector of L. tropica elsewhere, is considered the cutaneous leishmaniasis vector in this emerging focus.

Distribution of phlebotomine sandflies, of the subgenus Larroussius, in Morocco.

Adult sandflies (Diptera: Psychodidae) of the genus Phlebotomus and of the subgenus Larroussius were collected with sticky traps from thirty-four localities in central and south-western Morocco. Four Larroussius species were present in this area, Phlebotomus perniciosus Newstead, being the most widespread and abundant species particularly in the mountainous area, was sympatric with the closely related species Phlebotomus longicuspis Nitzulescu. Only one male of P. perniciosus displayed the bifid copulatory valves characteristic of the species. All specimens showed copulatory valves curved at their apex. The number of coxite hairs is a taxonomical tool that differentiates this morph of P. perniciosus from P. longicuspis. Phlebotomus ariasi Tonnoir was collected from six mountainous stations. Phlebotomus mariae Rioux et al. was scarce; only five males were collected and were often associated with P. ariasi.

Togetherness among Plasmodium falciparum gametocytes: interpretation through simulation and consequences for malaria transmission.

Previous experimental gametocyte infections of Anopheles arabiensis on 3 volunteers naturally infected with Plasmodium falciparum were conducted in Senegal. They showed that gametocyte counts in the mosquitoes are, like macroparasite intakes, heterogeneous (overdispersed). They followed a negative binomial distribution, the overdispersion coefficient seeming constant (k = 3.1). To try to explain this heterogeneity, we used an individual-based model (IBM), simulating the behaviour of gametocytes in the human blood circulation and their ingestion by mosquitoes. The hypothesis was that there exists a clustering of the gametocytes in the capillaries. From a series of simulations, in the case of clustering the following results were obtained: (i) the distribution of the gametocytes ingested by the mosquitoes followed a negative binomial, (ii) the k coefficient significantly increased with the density of circulating gametocytes. To validate this model result, 2 more experiments were conducted in Cameroon. Pooled experiments showed a distinct density dependency of the k-values. The simulation results and the experimental results were thus in agreement and suggested that an aggregation process at the microscopic level might produce the density-dependent overdispersion at the macroscopic level. Simulations also suggested that the clustering of gametocytes might facilitate fertilization of gametes.

Limitation and facilitation in the vectors and other aspects of the dynamics of filarial transmission: the need for vector control against Anopheles-transmitted filariasis.

In certain filaria-mosquito combinations, the number of infective, third-stage larvae (L(3)) that develop in a mosquito is not proportional to the number of microfilariae (mff) ingested by that mosquito. As the number of mff ingested increases, the yield of L(3) per microfilaria may either increase (in a process known as 'facilitation') or decrease (in a process known as 'limitation'). Each ingested microfilaria that is successful (in terms of reaching the haemocoel) increases (facilitation) or decreases (limitation) the 'permeability' of the stomach wall for the next microfilaria. Limitation is seen in some culicine mosquitoes, especially the Aedes spp. that transmit Wuchereria bancrofti, which, in consequence, become relatively more efficient as vectors as they ingest fewer mff. This phenomenon makes the interruption of filarial transmission by Aedes spp. particularly difficult. As the survival of anopheline mosquitoes is adversely affected by filarial infection, the use of mass drug administrations (MDA) to reduce the prevalence and intensity of microfilaraemias may increase the mean lifespan of some of the local Anopheles species. If these same species also act as vectors of malarial parasites, effective, drug-based control of W. bancrofti may worsen the problem posed by malaria. Therefore, wherever malaria and bancroftian filariasis are co-endemic and caused by parasites transmitted by the same species of mosquito, MDA should be augmented by interventions (use of bednets or house-spraying) against adult Anopheles.

High heterogeneity in the number of Plasmodium falciparum gametocytes in the bloodmeal of mosquitoes fed on the same host.

To investigate the quantitative distribution of Plasmodiumfalciparum gametocytes into the vector bloodmeal, Anopheles arabiensis mosquitoes were fed on 3 volunteers naturally infected with gametocytes. The content of each mosquito midgut was smeared on a microscope slide and Giemsa stained. The distribution of gametocytes ingested by mosquitoes followed a negative binomial distribution, with apparently constant overdispersion (parameter k +/- S.E. = 3.105 +/- 0.392) for the 3 series. This aggregation of gametocytes in some midguts probably facilitates the conjunction of gametes and fertilization. This suggests that P. falciparum gametocytes in the peripheral blood flow of infected man do not follow an independent, homogeneous pattern but show a significant aggregation.

Intraoperative clonidine enhances postoperative morphine patient-controlled analgesia.

In this prospective study, the postoperative analgesic effects of intraoperative iv clonidine were evaluated. Two hundred consecutive patients undergoing major abdominal surgery were randomly assigned to either balanced anaesthesia with iv clonidine (Group 1) or balanced anaesthesia alone (Group 2). A PCA infuser was connected immediately after tracheal extubation. It was programmed to deliver morphine "on demand" iv boluses at doses of 1 mg for patients greater than 65 yr and 1.5 mg for women or 2 mg for men less than 65 yr old. A blinded observer assessed postoperative analgesia by recording the analgesic demands (both met and unmet), patient pain scores, sedation scores, and any side effects during the first 36 hr after surgery. Intraoperative clonidine reduced the number of analgesic demands during the observation period (45 +/- 27 demands in Group 1 vs 81 +/- 60 in Group 2, P = 0.0001). This resulted in a reduction in morphine delivered (55.4 +/- 30.6 mg vs 67.1 +/- 45.1 mg, P less than 0.05), mainly during the first 12 hr (19.7 +/- 11.1 mg vs 27.6 +/- 18.1, mg P less than 0.001) and the unmet demand rate was also reduced at all time intervals (P less than 0.01). Clonidine did not exacerbate sedation or side effects. However, clonidine provided better analgesia in men and in patients less than 65 yr of age. Intraoperative iv clonidine enhances morphine analgesia after abdominal surgery.

Population dynamics of Loa loa and Mansonella perstans infections in individuals living in an endemic area of the Congo.

A follow-up of Loa loa and Mansonella perstans microfilaremia was carried out in an adult population living in a highly endemic area of the Congo. Infection rates and parasite loads were found to be stable in the general population, both in the short-term (two months) and long-term (3-4 years) followup. The microfilarial status of most of the subjects examined did not change between tests. At the individual level, the microfilarial densities of L. loa and M. perstans also remained remarkably constant over time. This results in a qualitative and quantitative stability of the parasitic material available for the vectors.

Crypto-periodicity in Mansonella ozzardi.

Studying nycthemeral microfilarial density in eight carriers of Mansonella ozzardi, Nathan et al. concluded that there is an absence of periodicity in M. ozzardi in Trinidad. Re-examination of the results obtained shows evidence of crypto-periodicity. Two of the eight patients showed highly significant periodicity but the biorhythms appear to be almost out of phase, the respective peaks being at 18.00 hours and 02.00 hours. The six other patients showed no obvious periodicity; the calculated acrophases (peak hours), instead of being randomly spaced, regrouped with the preceding ones: late afternoon in two subjects and in the second half of the night for the other four. It is concluded that the apparent non-periodicity is due to the co-existence of two periodic forms, but these are markedly out of phase.

[Intake of microfilariae by the vector in the case of a low microfilareamia (author's transl)]. / Ingestion des microfilaires par le vecteur dans le cas des basses microfilaremies.

The study of the intake of microfilariae of Dipetalonema dessetae by Aedes aegypti leads to two conclusions with respect to the microfilaraemia: --there is no concentration of microfilariae in the uptake of blood by Aedes. --the microfilariae are nearly homogeneously distributed in the vertebrate host blood available to the vector for feeding. Such a distribution of microfilariae in the cutaneous blood supply of the host gives the maximum chance for a mosquito to become infected when taking a blood meal. In the pair Wuchereria bancrofti--Aedes polynesiensis the capacity of individuals with a low microfilaraemia to transmit infections seems to be related to a limitation phenomenon.

[Fluctuations affecting the measurement of microfilaremia (author's transl)]. / Etude statistique de la variabilité caractérisant les mesures de la microfilarémie capillaire.

A statistical analysis was conducted, in order to compare the variations in values of a) blood samples obtained with several finger-pricks from the same individual in a short period of time, and b) blood samples obtained from the same finger-puncture. No significant difference was observed: both groups seem to follow a negative binomial distribution, the exponent of which is not dependent on the microfilarial count average. This common exponent is roughly equal to the volume of the blood sample, expressed in cmm.

[Dengue outbreak by virus type 4 in French Polynesia. I. General epidemiology - clinical specific aspects (author's transl)]. / La dengue due au virus de type 4 en Polynésie Francaise. I.--Epidémiologie générale aspects cliniques particuliers.

Authors describe an extensive outbreak of dengue 4 virus which is observed for the first time out of its Asian original focus. The whole archipelagos of French Polynesia have been contaminated in a space of four months. Usual form of the disease is typical with lightness of the symptoms. This outbreak has been implicated in the death of a child by shock; and two cases of reversible encephalitis have been certainly caused by this virus. The neurotropism is the main characteristic of dengue virus type 4.

[Dengue outbreak by virus type 4 in French Polynesia. II. Preliminary biological observations on epidemiology and physiopathology of the disease (author's transl)]. / La dengue due au virus de type 4 en Polynèsie Francaise. II.--Observations biologiques liminaires sur quelques points prècis d'èpidèmiologie et de physiopathologie.

Authors report some accurate epidemiologic and physiopathologic data about dengue 4. Thanks to virus intrathoracic inoculation in Toxorhynchites amboinensis (Doleshall, 1857), 202 viral strains have been isolated from 633 sera samples. The incidence of the disease has decreased very early after immunization of the whole population and resulted in an eradication of dengue type 1 virus which was endemic in French Polynesia since 1976. Only one type of dengue virus seems to be tolerated in French Polynesian ecosystem in the same time. There is no crossing protection with dengue 1. Clinically, the picture has been the same in both new and previously infected by dengue 1 patients. Duration of viremia during the secondary dengue fever is not shorter than in the primary one. The hemagglutination inhibiting antibodies do not protect patients, but do not result in immune-complexes pathology.

[Studies of the numerical distribution of microfilariae in foci of lymphatic filariasis (author's transl)]. / Etude de la distribution des numérations microfilariennes dans les foyers de filariose lymphatique.

The frequency distribution of Wuchereria bancrofti microfilariae counts in capillary blood, at a community level, is shown to differ significantly from the log-normal distribution, commonly used (and recommended by WHO). A much better fit is obtained with a truncated negative-binomial distribution, the k exponent of which is estimated to 0.3. This value does not seem to be affected by the endemic level, by microfilaricide mass-treatments or by the blood sample volume. This result has immediate practical interests: 1) it facilitates a posteriori comparisons between surveys in which different volumes of blood were examined; 2) at a given density it allows calculation the change in sensitivity (detection rate) as a function of a change in the volume of blood examined, thus allowing better a priori planning of surveys. The paper provides the formulae required to calculate k, or, given k, to calculate the expected numbers in the various density classes. It also provides nomograms (fig. 4a & b) giving estimates of the true mean M and of the detection rate TD, given any one of the three following observations, made on observed positives: the median Dmf. 50, the mean m, or the percentage Pl having only 1 mf. The effect of changing the volume of blood on the rate of detection can then be read easily from the nomogram. These results, likely to apply to other important parasitic diseases, should instigate more elaborated statistical research in this direction.

[Evolution of filarial hemagglutinating antibodies 1 year after a single dose of diethylcarbamazine]. / Evolution, en matière de filariose, des anticorps hémagglutinants un an après une dose unique de diéthylcarbamazine

The authors compare the serological results obtained before and after a single dose with diethylcarbamazine (6 mg./kg.) in a homogeneous and strongly infected with Wuchereria bancrofti var, pacifica population. They point out a statistically significant decrease of the hemagglutining antibody titres of filarian patients.