[Risk of arbovirus transmission by ticks in Thailand]. / Le risque de transmission d'arbovirus par les tiques en Thailande.

Ticks are known vectors of transmission for a number of infectious viral diseases from wild or domestic animals to humans. Many tick-borne diseases cause severe clinical syndromes such as encephalitis or hemorrhagic fever. Animal carriers of enzootic diseases are often asymptomatic. Within the framework of a program to monitor emerging viral diseases in Southeast Asia, identification of ticks capable of transmitting diseases from animals to man is a prerequisite for epidemiologic study to assess the risk of tick-borne disease. The purpose of this report is to provide an update on the situation based on a study of tick fauna in the central plain area of Thailand and on current knowledge about tick-borne arboviruses in Asia. In addition to an exhaustive inventory of ticks found in Thailand, this study describes the viruses with pathogenic potential that ticks are known to carry and transmit to man. A perusal of the literature allowed initial assessment of the risk for introduction and spread of ticks by bird hosts in Southeast Asia as well as of associated virus.

Comparisons of two groups of sex-change applicants based on the MMPI.

Out of 29 men asking for a sex-change, 16 reported clinical anamnesis criteria for transsexualism according to the DSM-III-R, a more restrictive diagnosis than the DSM-IV gender dysphoria diagnosis. In addition, all the subjects had taken an MMPI which, of course, did not contribute to the transsexualism diagnosis but which served to describe their personalities. The 16 subjects diagnosed as transsexual and the 13 who did not qualify for this diagnosis were compared on the basis of personality variables measured by the MMPI. Certain differences became evident. The transsexuals systematically complied to cultural stereotypes of femininity without any uneasiness, whereas the nontranssexuals could be subdivided into two groups, those with a vague sense of ill-being linked to a pronounced feminine identity or those with only a slight feminine identity and who showed no particular difficulties.

[Experimental transmission of Crimean-Congo hemorrhagic fever virus by Rhipicephalus evertsi evertsi (Acarina:Ixodidae)]. / Transmission expérimentale du virus de la fièvre hémorragique de Crimée-Congo par la tique Rhipicephalus evertsi evertsi (Acarina: Ixodidae).

We have conducted experiments to assess the ability of Rhipicephalus evertsi evertsi tick to transmit the Crimean-Congo haemorrhagic fever (CCHF) and determine their reproductive cycle. The Rh. e. evertsi was infected by intracoelomic (transparietal and intra-anal) inoculation during the imaginal stases and by oral feeding on an infected viremic goat during imaginal and nymphal stases. The infection rate, transovarial and trans-stasial CCHF virus transmission were monitored for virus reisolation after suckling mice inoculation and the virus identified by ELISA and IFA for antigen detection. After intracoelomic inoculation, unfed adults had viral titers ranging from 0.67 to 2.9 log DL50/0.02 ml and had transmitted the virus to their vertebrate hosts by blood feeding. After 8 to 10 days of blood feeding duration, infection rates were respectively 36% and 100% for male and female ticks. In two instances out of seven transovarial transmission was observed and the virus reisolated from larvae of first generation. However, the virus was not detected after nymphal metamorphosis. After blood feeding on viremic goats, 71% of the nymphae were infected. After metamorphoses 22% of the males and 42% of the females had a low virus titer. Rh. e. evertsi appears to have a limited efficacy in transmitting and replicating the CCHF virus but must be not neglected as a potential vector during an epizootic manifestation.

Inappropriate calls to an emergency medical despatch centre via cellular telephones--no impact of a once-only multimedia coverage.

Due to fusions of emergency despatch centres, implementation of computer-aided localization and medical regulation, the despatcher's workload is increasing. We report about one more phenomenon which is needlessly disorganizing alarm centres. Moreover, the unintentional activation of the '100' ('112') alarm centre continued to increase even after a once-only media campaign.

[Experimental transmission of Crimean-Congo hemorrhagic fever virus: role of 3 vector species in the maintenance and transmission cycles in Senegal]. / Transmission expérimentale du virus de la fièvre hémorragique de Crimée-Congo: place de trois espèces vectrices dans les cycles de maintenance et de transmission au Sénégal.

In this article, we published the role of three species of ticks Amblyomma variegatum (Fabricius, 1974), Hyalomma marginatum rufipes (Koch, 1844) and Hyalomma truncatum (Koch, 1844) in the maintenance and transmission of the CCHF virus. The imagos of these species were infected by intracoelomic route. Vertical transmission (transtasial and transovarial) and horizontal transmission for different stases were studied by isolation on newborn mice, polymerase chain reaction, indirect immunofluorescence and ELISA. Our results proved that 15 days after inoculation, infection rates of 100% were noted with Hyalomma marginatum rufipes and Hyalomma truncatum. This rate is about 60% for Amblyomma variegatum. The imagos of the three species infected have transmitted the virus to their host during blood feeding (100%). A high transovarial transmission for Hyalomma marginatum rufipes and Hyalomma truncatum were observed (respectively 53 and 50%). This rate is about 12% for Amblyomma variegatum. The tick infection does not persist up to the first generation for the three species studied. Ticks are temporary reservoirs vectors but not permanent reservoirs of CCHF virus.

Biological and clinical responses of west African sheep to Crimean-Congo haemorrhagic fever virus experimental infection.

West African sheep appear to play a central role as virus hosts in the maintenance cycle of Crimean-Congo haemorrhagic fever (CCHF) virus in endemic areas and also because of their role as a principal host of the CCHF virus tick vector. In an effort to clarify CCHF epidemiological significance in sheep, we studied the biological and clinical aspects of sheep experimentally infected with CCHF virus. West African sheep breeds were infected either by intraperitoneal inoculation or by infestation with experimentally CCHF-virus-infected ticks (Hyalomma truncatum). A total of 17 sheep including controls as well as 5 lambs from their progeny were monitored. A moderate but constant fever was observed (39.7 degrees C +/- 0.3) which correlates with the viraemia. Virus was reisolated from blood samples taken from day 3 to day 9 postinfection (p.i.) at a mean titre of 3.3 log LD50/ml. The virus was detected for a period of time of 7 days in non-immune sheep and for less than 4 days in previously immunized sheep. In non-immune sheep, antibody detected by ELISA showed an IgM response on day 7 p.i., followed by an IgG response one day later. Five infected sheep, surveyed for liver and kidney biological markers, showed hepatic dysfunction with a moderate serum aspartate transferase rise to 210 U/l. Out of four sheep tested for blood markers, two showed an abnormal blood cell count, with marked neutrophilia of up to 63% lasting for two weeks. Infected pregnant ewes produced antibodies in their milk at a significant titre (1:1,000), and antibodies were recovered in the sera of nursing lambs from their first meal to 50 days after birth. These findings are discussed; they demonstrate that, in spite of a high turnover of local sheep herds (median age of 3 years) and long-term CCHF antibody persistence (> 3 years), sheep can be infected and efficiently transmit the virus at least once in a lifetime.

Crimean-Congo hemorrhagic fever in ticks (Acari: Ixodidae) and ruminants: field observations of an epizootic in Bandia, Senegal (1989-1992).

From 1989 to 1992, a longitudinal study of the relationships between different tick species and domestic ungulates in the transmission and amplification of Crimean-Congo hemorrhagic fever (CCHF) virus was undertaken in the Bandia area in Senegal where the presence of the virus had been reported previously. An epizootic occurred in 1991-1992 and 22 strains of CCHF virus were isolated from Hyalomma marginatum rufipes Koch, Amblyomma variegatum (F.), Rhipicephalus guilhoni Morel & Vassiliades, and R. evertsi evertsi Neumann ticks collected from cattle and goats. No human cases were reported. Transmission of CCHF virus in the area involves a complicated pattern including many tick species and hosts. Amplicons of the S fragment (536 bp) of the CCHF genome of 12 isolates from the study were obtained by polymerase chain reaction and analyzed by restriction-length fragment polymorphism. Three different genotypes of CCHF virus were identified and present during the epizootic. One genotype was recovered from A. variegatum, R. guilhoni, and R. e. evertsi and 2 genotypes were isolated from H. m. rufipes.

Evaluation of the effects of mivacurium chloride on hemodynamics and left ventricular function in patients with coronary artery disease undergoing abdominal aortic surgery.

OBJECTIVE: To determine the effects of two doses of mivacurium chloride on hemodynamics and left ventricular function in patients with documented coronary artery disease undergoing aortic surgery. DESIGN: A prospective study with the dose of mivacurium determined by randomization. SETTING: Induction area at a university hospital. PARTICIPANTS: Twenty consecutive patients undergoing aortic surgery with clinically and/or angiographically documented coronary artery disease. INTERVENTIONS: Intravenous administration of mivacurium chloride. MEASUREMENTS AND MAIN RESULTS: Induction of anesthesia was performed with midazolam and fentanyl. Two different doses of mivacurium chloride, 0.15 mg/kg (n = 10) and 0.2 mg/kg (n = 10; 2 and 2.5 ED95; respectively), were administered as a single bolus injection over a 60-second period in the absence of any surgical stimulation. In addition to standard hemodynamic monitoring, pulmonary artery catheterization and transesophageal echocardiography were used. The occurrence of myocardial ischemia was monitored using both a computerized three-lead ST-segment analysis system and the echocardiographic assessment of regional wall motion. No change in heart rate, mean arterial pressure, pulmonary capillary wedge pressure, cardiac output, and global left ventricular function was noted after administration of mivacurium with the two doses studied. No ST-segment change or new segmental wall motion abnormality was noted in either group. CONCLUSION: Mivacurium chloride, when injected over a 60-second period, preserves global and regional myocardial function in patients with documented coronary artery disease undergoing noncardiac surgery.

Host-passage-induced phenotypic changes in crimean-congo haemorrhagic fever virus.

Changes in virulence of Crimean-Congo haemorrhagic fever (CCHF) virus toward intracerebrally inoculated suckling mice (SM) were studied in relation to different host-passage histories. Two CCHF virus strains, one isolated from a human and the other from a tick, were passaged through various vertebrate and tick hosts and then reisolated and tested for their virulence toward SM. In various experiments, SM were inoculated with 12 different viral suspensions, each having a specific passage history. Survival curves of SM, which may reflect differences in viral strain characters, were established using an actuarial life table; differences were evaluated with the log-rank test. Regardless of the origin of the strain, CCHF viruses exhibited pathogenicity when passaged among SM. However, virulence, as measured by the proportion of deaths in SM, was altered following passage through another vertebrate host or tick. The final host seems to have a major influence on virulence. Because CCHF virus strains appear to vary little in their antigenic characters, it is hypothesized that hosts can induce phenotypic changes that modulate viral virulence.

Experimental transmission of Crimean-Congo hemorrhagic fever virus by west African wild ground-feeding birds to Hyalomma marginatum rufipes ticks.

Hyalomma (H.) marginatum rufipes ticks commonly infest birds and are potential vectors of Crimean-Congo hemorrhagic fever (CCHF) virus in west Africa. An experimental model for investigating the role of birds in the CCHF virus transmission cycle was developed. Following CCHF virus inoculation, antibodies were detected by enzyme-linked immunosorbent assay in one red-beaked hornbill and one glossy starling, but not in two laughing doves and six domestic chickens. None of the birds showed a detectable viremia. Hyalomma marginatum rufipes larvae were placed on three red-beaked hornbills and one glossy starling. These birds were then inoculated with CCHF virus (10(1.5) 50% mouse intracerebral lethal doses). Virus transmission to larvae or nymphs was obtained and seroconversions in birds were recorded. Virus was also detected in 90% of the individually tested nymphs, as well as in adults. The virus was then successfully transmitted by adult ticks to rabbits and the engorged females were allowed to oviposit. Progeny larvae were placed on another group of birds and one of three birds showed seroconversion. The cycle of transmission of virus between ticks and aviremic ground-feeding birds represent a potential reservoir and amplification mechanism of CCHF virus in west Africa.

Crimean-Congo haemorrhagic fever virus infection in birds: field investigations in Senegal.

In Senegal, wild ground-feeding birds are frequently infested with immature ticks. In two areas where numerous Crimean-Congo haemorrhagic fever (CCHF) virus isolations were obtained from Hyalomma marginatum rufipes adult ticks collected on ungulates, 175 birds were captured and sera collected. CCHF antibodies were detected by ELISA in 6/22 red-beaked hornbills (Tockus erythrorhynchus), 2/11 glossy starlings (Lamprotornis sp.) and 1/3 guinea fowls. The virus was isolated from H. m. rufipes nymphs collected on a hornbill. The role of wild ground-feeding birds in CCHF virus ecology in West Africa is discussed.

Identification of rickettsiae from ticks collected in the Central African Republic using the polymerase chain reaction.

Spotted fever rickettsiosis have been identified on the African continent since their historical description in 1909. However, only Rickettsia conorii and R. africae have been described in Africa, and the current techniques for the detection of rickettsiae in ticks are difficult to apply in large field studies. We report here a preliminary study using genomic amplification by the polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) analysis directly on 310 crushed ticks (Rhipicephalus, Amblyomma, and Haemaphysalis species) collected in 1985 in the Central African Republic. Among 310 specimen tested, 21.6% were positive. The rate of infection ranged from 0% to 64.3%, depending on the tick species. Based on PCR-RFLP, five different rickettsiae profiles were found: R. conorii and R. africae, previously known in Africa, R. rhipicephali, which has never been described in Africa, and two isolates identical to R. massiliae and Mtu5, previously obtained from Rh. turanicus in southern France. This work shows that PCR-RFLP is a powerful tool to study tick collections, and that it is applicable to samples from developing countries. Further work is needed to confirm the identification of the rickettsiae found in this work, using traditional identification procedures.

[Crimean-Congo hemorrhagic fever in Senegal. Latest data on the ecology of the CCHF virus]. / La fièvre hémorragique de Crimée-Congo au Sénégal. Dernières données sur l'écologie du virus CCHF.

The authors finalize the knowledge on the ecology of the CCHF virus in Senegal, West Africa. They specify two new major data for the understanding of the viral ecology in West Africa. The recognition of a bird species, common and widely distributed in Senegal (Tockus erythrorhynchus, Coraciiformes, Bucerotidae), that replicates the virus and infects the immature stages of its current parasite Hyalomma marginatum rufipes in more than 90% of the cases, explains why the minimum infection rate of the adults of this species of tick is always very high. The implication of Rhipicephalus evertsi evertsi in the viral ecology and/or a high efficiency of the transovarial transmission of the virus in Hy. m. rufipes would help to explain the maintenance of the endemy in the sahelian area. In the sahelian zone, Hy. marginatum rufipes must play the leading part, together with Rh. e. evertsi if vector, for the maintenance of the endemy. Hy. truncatum, the adults of which can readily bite man, ensures the vectorial transmission to him. In the sudanian zone, Amblyomma variegatum must play the same part as the Hyalomma and Rh. e. evertsi (if vector), and is surely the main vector to man, giving perhaps rise to less virulent strains (non hemorrhagic ones).

Evaluation of the effects of rocuronium bromide on haemodynamics and left ventricular function in patients undergoing abdominal aortic surgery.

In an open study of 26 patients undergoing abdominal aortic surgery, the effects of rocuronium 0.6 mg kg-1 (eight patients) and 0.9 mg kg-1 (nine patients) were compared with those of pancuronium 0.085 mg kg-1 (eight patients) on haemodynamic parameters and transoesophageal echocardiography. The anaesthetic technique was based on a benzodiazepine and low dose fentanyl (6 micrograms kg-1). Pancuronium was associated with a significant increase in mean arterial pressure, end-diastolic area and heart rate, none of which were seen after rocuronium at either dose level.

Association of ticks (Acari: Ixodoidea) with rodent burrows in northern Senegal.

Four species of ticks were retrieved from burrows of 64 multimammate rats, Mastomys erythroleucus (Temminck), 55-gerbils, Taterillus gracilis (Thomas) or T. pygargus (Cuvier), 13 Nile rats, Arvicanthis niloticus (DeMarest), and five Geoffroy's ground squirrels, Xerus erythropus (Geoffroy) from May 1987 through August 1988 at two study sites in northern Senegal. Ornithodoros sonrai Sautet & Witkowski were recovered from 95% (74/78) of burrows near Bandia and 6% (4/66) of burrows near Yonofere. Eight Hyalomma truncatum Koch, four Rhipicephalus guilhoni Morel & Vassiliades, and one R. sulcatus Neumann were recovered from 144 rodent burrows (nine tick-positive burrows) from both locations. No seasonal trend of tick abundance or activity was noted, nor was any pattern of burrow preference by ticks detected. Rodent burrows in either location appeared to be little used by ixodid ticks.

Sexual and transovarian transmission of Crimean-Congo haemorrhagic fever virus in Hyalomma truncatum ticks.

Male Hyalomma truncatum ticks were inoculated with Crimean-Congo haemorrhagic fever (CCHF) virus, hypostomectomized and then allowed to mate with uninfected females feeding on a naive rabbit. After mating, CCHF virus was reisolated from 2 out of 3 males tested and from 4 of 6 mated, engorged females (titre greater than or equal to 2.2 log LD50/ml). Vertical transmission was then demonstrated by virus reisolation from a portion of 2 of the 6 batches of eggs laid by the positive females. From these 2 positive egg batches, 6 larvae pools were tested with successful virus reisolation from one. Attempts to reisolate CCHF virus from 15 nymph pools of this positive batch of larvae were unsuccessful. Virus reisolation from gonopore-closed female H. truncatum which cofed with preinfected males demonstrated transmission in the absence of copulation. Rabbits that served as bloodmeal sources seroconverted after infestation by infected male ticks. However, CCHF virus was not reisolated from 3 gonopore-closed, engorged females, nor from their eggs, after feeding with hypostomectomized preinfected males. Transmission of CCHF virus during mating or cofeeding of adult H. truncatum, and subsequent transovarial transmission, appear to represent additional mechanisms of infection in the tick population, and may contribute to the maintenance of transmission in nature.

Crimean-Congo haemorrhagic fever virus replication in adult Hyalomma truncatum and Amblyomma variegatum ticks.

The kinetics of the replication of the Crimean-Congo haemorrhagic fever virus (CCHFV) was studied in intra-anally inoculated adult Hyalomma truncatum and Amblyomma variegatum ticks. The virus was re-isolated by suckling mouse inoculation and revealed by antigen capture with ground ticks and indirect immunofluorescence of haemolymph. The virus was detected in ticks in the first hours post-inoculation (p.i.) and its replication was observed from 36 h p.i. onwards. Virus titre reached a maximum within 3-5 days then decreased slowly to a level of at 2 log LD50/ml for several months until the end of observations. Several specific, non-identified factors seem to favour CCHFV replication in H. truncatum. Long-term virus persistence seems to occur in CCHFV-infected adult ticks.

Transmission of Crimean-Congo haemorrhagic fever virus from experimentally infected sheep to Hyalomma truncatum ticks.

Crimean-Congo haemorrhagic fever (CCHF) virus was inoculated into West African sheep that were simultaneously infested with adult Hyalomma truncatum ticks. Certain sheep developed a viraemia and antibodies, indicating virus infection and replication; however, the length and magnitude of the viraemia and serological responses corresponded to the animals' immunological status. Tick attachment and feeding was not influenced by sheep infection. CCHF virus infection was acquired by 11-33% of female and 0-60% of male ticks. Infection in the ticks did not influence their feeding success, as judged by weight at drop-off, and the weight of eggs produced by infected and non-infected ticks was similar. Transovarial transmission of CCHF virus was demonstrated in 2 of 12 (17%) egg batches from infected female ticks, but in none of 19 egg batches from ticks that tested negative for CCHF virus. Our results suggest that under certain ecological conditions, sheep may serve to amplify CCHF virus in nature through horizontal transmission and that the maintenance cycle also may be influenced by transovarial transmission to the next generation of ticks.

Tick-borne borreliosis in west Africa.

Reported cases of tick-borne relapsing fever due to the spirochaete Borrelia crocidurae are rare in West Africa, and few epidemiological data are available. To see how common relapsing fever is in Senegal thick blood smears from cases of fever of unknown origin and from randomly selected clinic outpatients from a rural dispensary were examined for Borrelia. The prevalence of Borrelia infections in small mammals was also assessed. Borrelia was seen in smears of 12 (0.9%) of 1340 children. All children who tested positive had complained of acute fever. Prevalence was 0% (0/496), 0.5% (2/417), 1.6% (5/308), and 4.2% (5/119) at ages 0-1, 2-4, 5-9, and 10-14, respectively. 26 other instances of borreliosis were seen in patients from different regions of Senegal. Blood samples from 7 of these patients were inoculated intraperitoneally into white mice; serious infection developed in all mice. Borrelia was seen in thick smears from 65 of 461 wild rodents or insectivores. Six rodents species were infected. From a sample of 93 rodents, 33.3% were infected, as judged by intraperitoneal inoculation of white mice, compared with 14.1% by direct smear examination. The findings suggest that borreliosis has a wide distribution and a high incidence in Senegal. This disease may be a major cause of morbidity in rural areas throughout much of West Africa.