4×10 Gbit/s bidirectional transmission over 2 km of conventional graded-index OM1 multimode fiber using mode group division multiplexing.

We demonstrate 4 × 10 Gbit/s error-free bidirectional transmission over 2 km of conventional OM1 graded-index multimode fiber using OOK modulation and direct detection. We also perform field transmission to show reach and capacity boosts on legacy multimode infrastructure. Such transmission is enabled by selective mode group division multiplexing, based on multi-plane light conversion over 4 mode groups of the multimode fiber.

Diagnostic methods used to monitor an outbreak of babesiosis (Babesia bovis) in a herd of feral cattle in New Caledonia.

BACKGROUND: In December 2007, Babesia bovis was introduced to New Caledonia through the importation of cattle vaccinated with a live tick fever (babesiosis and anaplasmosis) vaccine. Medical measures, acaricide and antiprotozoal treatments, and quarantine restrictions were implemented with success on all the farms involved, but the disease spread to one of the neighbouring properties where feral cattle were present. To circumscribe and eliminate this outbreak, the authorities decided to slaughter all animals on the neighbouring property. OBJECTIVES: To monitor the spread of babesiosis in naïve cattle and to compare the usefulness of PCR, ELISA and brain smear for disease detection in monitoring this outbreak. METHODS: Blood and brain samples of slaughtered animals were analysed over time throughout the eradication campaign using serology, PCR and brain smears. In addition, field numbers of Rhipicephalus microplus tick larvae were assessed and Babesia infection of the larvae analysed using PCR. RESULTS: This study showed the natural spread of babesiosis in a naïve herd without pharmacological control measures. Prevalence reached 80% within a year of introduction. ELISA and PCR tests performed similarly in detecting disease in cattle and both were superior to brain smears. Nevertheless, specific tests or combinations of tests may be preferable, depending on the specific requirements of any future disease situation. CONCLUSIONS: In cattle, ELISA and PCR appear to be suitable tools for monitoring the evolution of a babesiosis outbreak, with brain smears as a useful adjunct. PCR was not suitable for detecting infection in tick larvae.

Swift sympatric adaptation of a species of cattle tick to a new deer host in New Caledonia.

The occurrence and frequency of sympatric speciation in natural systems continue to be hotly debated issues in evolutionary biology. This might reflect the timescale over which evolution occurs resulting in there being few compelling observations of the phenomenon (lake fishes, phytophagous insects and Island trees). Despite predictions, few examples of sympatric speciation have been recorded in animal parasites, at least widely accepted as such. Here we show that, in New Caledonia, the monophasic (exploiting one individual host per generation) cattle tick Rhipicephalus microplus has evolved in contact with two sympatric host species into two differentiated genetic pools: on the cattle, its original host and on rusa deer, a new host for this tick. This sympatric isolation has occurred over a relative short period of time (i.e. less than 244 tick generations) as a consequence of differential selection pressure imposed by hosts. It is most likely that this phenomenon has occurred in many other places across the globe where this tick has come in contact with different host species in sympatry with cattle.

Spread of parasites transported with their hosts: case study of two species of cattle tick.

Like all parasites, ticks can be spread easily along with their hosts. Ticks are obligate parasites of vertebrates, to which they attach themselves for varying periods of time, and are well-adapted to this mode of transport. Once the transport stage is complete and they have detached at destination, they are also able to wait several months for the arrival of a new host on which they will continue their life cycle. This leads to the establishment of a secondary tick population. Two tropical cattle tick species, Rhipicephalus microplus and Amblyomma variegatum, have perfected this strategy of colonisation and occupation of favourable zones. Rhipicephalus microplus, which originated from South and Southeast Asia, is highly specific for ungulates, and thanks to cattle movements it has spread throughout the tropical belt, apart from the remotest areas. Amblyomma variegatum, which originated in Africa, was transported to Madagascar and the Mascarene Islands, as well as to the West Indies, during the time of the Atlantic triangular trade. These two ticks are vectors of particularly serious cattle diseases: babesiosis and anaplasmosis in the case of R. microplus, and heartwater (cowdriosis) in the case of A. variegatum. Anticipated climate changes are likely to modify the potential geographical range of these two parasite species and numerous others. Even now there are still many areas of the Americas, Asia and Oceania into which A. variegatum has not yet spread, but which it would find favourable. It could be spread not only by the transport of cattle, but also by the migration of some of its other hosts, such as birds. Surveillance--and know-how--is needed to identify these parasites when they first appear and to rapidly contain new outbreaks. Efforts should be made to raise the awareness of livestock professionals about the risks of transporting cattle. Regulations should be implemented and precautions taken to avoid such artificial expansion of the range of ticks and the diseases they transmit.

Population genetic structure of wild and farmed rusa deer (Cervus timorensis russa) in New-Caledonia inferred from polymorphic microsatellite loci.

Historical records indicate that 12 rusa deer (Cervus timorensis russa) were introduced in New-Caledonia during the 1870s. We used eight polymorphic microsatellite DNA loci to assess the genetic differentiation and diversity of farmed and wild deer populations. Past genetic bottlenecks were detected in both sub-populations, although higher genetic diversity was maintained in farmed populations, probably due to the regular introduction of reproducers from wild populations and from other farms. The genetic structure of farmed and wild populations differed significantly. There was a significant isolation by distance for wild populations, whereas farmed populations were significantly differentiated between farms independently from their geographical proximity. Wild rusa deer consisted of small populations (with effective population sizes ranging between 7 and 19 individuals depending on the methods used), with a low parent-offspring dispersion range (0.20-2.02 km). Genetic tools and direct observations provided congruent estimates of dispersion and population sizes. We discuss the relevance of our results for management purposes.

Nuclear charge radii of neutron-deficient lead isotopes beyond N = 104 midshell investigated by in-source laser spectroscopy.

The shape of exotic even-mass (182-190)Pb isotopes was probed by measurement of optical isotope shifts providing mean square charge radii (delta(r(2))). The experiment was carried out at the isolde (cern) on-line mass separator, using in-source laser spectroscopy. Small deviations from the spherical droplet model are observed, but when compared to model calculations, those are explained by high sensitivity of delta(r(2)) to beyond mean-field correlations and small admixtures of intruder configurations in the ground state. The data support the predominantly spherical shape of the ground state of the proton-magic Z=82 lead isotopes near neutron midshell (N=104).

Using invaded range data to model the climate suitability for Amblyomma variegatum (Acari: Ixodidae) in the New World.

Climate matching models are in increasing use to predict distributions of living organisms, using records of the known distribution of a species to map its expected range of habitat suitability. Here, we modelled the known distribution of the tick Amblyomma variegatum in Africa as a preliminary step to delineate the most probable range of climatically suitable habitat for the tick in the New World. We used two presence-only methods (one based in the Gower distance, the other based on the Maximum Entropy principle) to model the distribution range in Africa. The Maximum Entropy method is highly dependent of the realized niche of the tick, and has serious constraints in the case of lack of adequate description of the actual range of the tick. The Gower distance, however, can evaluate the fundamental niche of the tick and produced better results with the same set of distribution data. Several populations of A. variegatum were recognized in Africa on the basis of statistically different ecological attributes. The separate modelling of the climate envelope for these populations provided a better fit in the delineation of habitat suitability with both methods in Africa but produced high rates of false negatives when applied to the Caribbean. The best modelling strategy for the tick in the New World (according to the rate of false negatives) is the use of Gower distance together with the known distribution of the tick in the Caribbean. The potential spread area of the tick includes all the Caribbean, large areas of Colombia and Venezuela, parts of Brazil, most of the Mesoamerican corridor and Mexico as well as the Peninsula of Florida. We do not consider further if the invading strain either still retains the full ecological plasticity of the original populations in Africa, or has already adapted to the invaded area, resulting in a more restricted ability to expand. Both possibilities have deep impact in our analyses, as the tick could find a larger zone for spreading into the New World.

Diagnosis of amitraz resistance in Boophilus microplus in New Caledonia with the modified Larval Packet Test.

The tick Boophilus microplus represents a serious pathological constraint to livestock production in New Caledonia. Cattle ticks are controlled by chemical application of two acaricides that are currently used in New Caledonia; deltamethrin is used at 46% of the cattle production facilities and amitraz at the remaining 54% premises where resistance to deltamethrin has been identified. In 2003, a modified Larval Packet Test (LPT) was used to conduct a survey for amitraz resistance. Ticks were collected from 29 farms, including farms using deltamethrin (n=8) or amitraz (n=21). Of eighteen different tick populations, sixteen populations were defined susceptible to amitraz and two populations were considered amitraz-resistant. This is the first report of populations of B. microplus being resistant to amitraz, using the modified LPT in New Caledonia. A thorough survey of tick susceptibility to amitraz in cattle farms of the country should be conducted to assess the presence of amitraz-resistant populations. The emergence of amitraz resistance so soon after its introduction has some important implications for the strategy and organisation of tick control in New Caledonia, and this paper discusses some of the urgent actions that should be undertaken.

[Rickettsia africae, the agent of African tick-bite fever: an emerging pathogen in the West Indies and Reunion Island (Indian Ocean)]. / Rickettsia africae, agent de la fièvre a tique africaine: un pathogène emergent dans les Antilles et l'lle de la Réunion.

Rickettsia africae is the agent of African tick bite fever, an emerging disease transmitted by Amblyomma ticks in sub-Saharan Africa. In 1998, we reported the first documented case of R. africae in the New World, in a patient who had returned from Guadeloupe. In order to confirm the presence of R. africae in the West Indies, entomologic surveys were conducted from 1999 to 2003 to collect Amblyomma, which are considered as potential vectors and reservoirs of the bacteria. Ticks were used as epidemiological tools to detect R. africae by molecular tools and/or cultivate the bacteria in shell-vial cell culture. This paper summarizes the results obtained in the West Indies. R. africae was detected and isolated for the first time in Guadeloupe, and then detected by molecular tools in Martinique and St-Kitts and Nevis. These last results confirm our first hypotheses--that is R. africae is prevalent on all the Caribbean islands where A. variegatum ticks have been introduced from Africa in the 18th and 19th centuries. We also present the results of a study conducted on the Reunion Island, a French island in the Indian Ocean. For the first time there, R. africae was detected in A. variegatum ticks, which were probably introduced from the African mainland or Madagascar with the human colonization during the 17th century Thus, clinicians should be aware that patient presenting in the West Indies or on Reunion Island (or after a trip over there) with fever, eschar (often multiple), regional lymphadenopathy and a rash, might be infected by R. africae.

Factors affecting the detachment rhythm of engorged Boophilus microplus female ticks (Acari: Ixodidae) from Charolais steers in New Caledonia.

As in most parts of the world where the cattle tick Boophilus microplus is established, resistance of ticks to acaricides occurs in New Caledonia. In order to implement laboratory resistance tests on larvae, engorged females collected in suspected farms are necessary. Investigations on the detachment schedule of the engorged females were conducted to explain certain field situations such as the lack or scarcity of engorged females on highly infested cattle driven from the pasture to the pen in the morning. Three experiments on Charolais steers naturally infested on pastures showed that: (1) engorged female burdens at sunrise are similar whether the steers spend the night in pasture or in a pen; (2) compared with steers maintained in a pen, morning detachment of females increases when the steers stay on the pasture or move from the pasture to the pen; (3) detachment rhythm of engorged females on steers staying the morning in a pen, is not influenced by feeding activity or exposition of steers to sun; (4) detachment occurs earlier for females attached on anatomical sites exposed to sun, and earlier from these sites for the steers in pasture or walking than for steers in a pen.

Factors related to cattle infestation level and resistance to acaricides in Boophilus microplus tick populations in New Caledonia.

Boophilus microplus, even in the absence of babesiosis, is a major disease of the cattle in New Caledonia where the particular farming system associates continental European breeds and a tropical climate tempered by the Pacific Ocean. In order to have a better understanding of the factors involved in cattle tick infestation, to decrease the possible wastage and use of chemicals and to increase the lifetime of the acaricides, the veterinary authorities investigated the conditions of the chemical treatments. A survey among 148 cattle farms of the whole of New Caledonia was carried out and factors that explain the development of tick resistance and cattle infestation have been determined. From this survey, three typologies for the main characteristics of the farms have been set up, the technical practices of the farmers and the tick control measures applied by the farmers, respectively. Some variables are significantly associated with the tick resistance to deltamethrin but their contribution to the explanation model is always moderate: farms in the south, with a positive resistance gradient from east to west, absence of bush fire and membership to a cattle farmers organization. The more the farmers have intensified their breeding-male castration, weaning, heifer separation, drenching, etc.-and pasture-high stock rate, mowing, extra feeding of the cows, many paddocks, etc.-techniques, the higher was the probability for the ticks in their farm to be resistant to deltamethrin. The technical details of the acaricide treatment had a low contribution to the explanation model. However, the use of a spray generated more resistance than a dip. Furthermore, there is a negative resistance gradient when the farmers increased the treatment interval average. Considering infestation, none of the variables from the three typologies were associated with the two infestation variables (1: semi-engorged tick females and 2: other ticks) at the herd level. However, the seven studied variables-the three typologies, breed, age, body condition score and breeding status-affected significantly the two infestation variables at the cow level, but their predictive ability remained very low (R(2)<3.5%). This result-individual effect more important than herd effect on the infestation-is confirmed by the importance of the variance of the intra-farm factors (99%) when compared with inter-farm factors (1%). Cows of Charolais breed, in poor body condition, old, pregnant or lactating, and those of the farms with irrational and high pressure control of ticks are the most infested.

Effect of the association of cattle and rusa deer (Cervus timorensis russa) on populations of cattle ticks (Boophilus microplus).

The wild population of rusa deer (Cervus timorensis russa) in New Caledonia (South Pacific) is nearly as large as the cattle population. The cattle tick is widespread and occurs all year round. Opinions are divided on the role of deer in the biological cycle of the tick: i) Do they maintain a sustainable tick population that is secondarily available for cattle? ii) Do they decrease the infestation of the environment by collecting larvae on the pasture, but preventing their development to the engorged female stage? or iii) Do they contribute to both situations? An experiment was conducted in three groups of pastures, each seeded with 450 000 larvae/ha and allowed to be grazed only by cattle, only by deer, and by a mixed herd of deer and cattle (deer representing 30% of the biomass), at approximately the same stocking rate (470-510 kg/ha). After 15 months of exposure, the tick burden per weight unit of host was 42 ticks/kg for the steers-only herd and 0.01/kg for the deer-only herd. The steers in the "mixed group" harbored 7 times fewer ticks (6.2/kg) than the cattle-only group, and the deer in the "mixed group," 130 times more (1.3/kg) than the deer-only group. Five emergency acaricide treatments had to be applied in the cattle-only group, but none in the other groups. The long-term sustainability of a viable tick population on deer as well as the potential benefit resulting from the association of deer and susceptible cattle in the tick control of cattle are highlighted.

Tick reference collection of the late Dr. P.C. Morel: a tool for tick taxonomists and veterinarians.

Host preference of ticks is an important, but still controversial, subject. Recent developments in molecular biology provide new opportunities to test some hypotheses about host preference in a given environment if appropriate specimens are available. Since the unique collection gathered by Dr. P.C. Morel could help achieve this goal, we present an overview of the samples available in his collection.

Role of Rusa deer Cervus timorensis russa in the cycle of the cattle tick Boophilus microplus in New Caledonia.

Two field experiments were conducted to evaluate the efficiency of Rusa deer in the development of the cattle tick Boaphilus microplus in comparison with that of steers in the same pastures and under the same conditions of infestation. No difference was noted between a mixed steer/deer herd and a pure steer or pure deer herd in the infestation pattern of each host, suggesting that attachment to the alternative host is mechanical and not affected by the simultaneous presence of the primary host on the pasture. Deer are capable of producing engorged viable females, with weight and reproductive performances similar to or even better than females fed on steers. For moderate levels (1 million larvae per hectare) and high levels (32 million larvae per hectare) of pasture infestation, tick burdens on steers were not very different (e.g. average 1,911 and 2,681 ticks per m2 skin, respectively, on day 24). This may be because of saturation of steer skin sites at the moderate larval dose. Deer harboured 2.7-33 times fewer ticks than steers and produce no engorged females at the moderate larval level and 32 times fewer engorged females than steers at the high larval level. Infestation of deer was dose-dependent with averages of 12 and 399 ticks per m2 skin on day 25 at the moderate and high larval levels, respectively. At a high infestation level of the environment, Rusa deer may contribute, but to a limited extent, to infestation of pastures and, consequently, of cattle. However, their role in sustaining a viable tick population requires further investigation.

Zebrafish keratin 8 is expressed at high levels in the epidermis of regenerating caudal fin.

Cytokeratins are structural proteins of the intermediate filament family and are mainly expressed in epithelial cells. In several vertebrates it has been shown that keratin 8 is expressed in simple epithelial tissues, some non-epithelial tissue and in hyper-proliferative tissues during development and tumor transformation. We previously cloned and characterised the zebrafish (Danio rerio) homologous cytokeratin 8 cDNA (zfk8) which was described as an epidermal marker during zebrafish development. It has been found that the zfk8 gene is normally expressed in simple epithelia in embryonic and mature zebrafish. Using whole-mount in situ hybridisation, we show in this report that expression of zfk8 is tightly linked to the regeneration of caudal fin and exclusively observed in epidermal cells. It is strongly expressed in the epidermis overlaying the inter-rays zone of regenerating caudal fin. Our results indicate that in zebrafish, cytokeratin 8 is a suitable epidermal marker during regeneration.

Influence of the MexA-MexB-oprM multidrug efflux system on expression of the MexC-MexD-oprJ and MexE-MexF-oprN multidrug efflux systems in Pseudomonas aeruginosa.

Of the Pseudomonas aeruginosa multidrug efflux systems, MexAB-OprM is expressed in wild-type cells, while MexCD-OprJ is not, and MexEF-OprN shows variable, strain-specific expression. In defined mutant strains, MexCD-OprJ expression increased with decreases in MexAB-OprM and was generally inversely related to MexAB-OprM expression. In so-called wild-type strains expressing MexEF-OprN, MexAB-OprM hyperexpression correlated with a decline in MexEF-OprN expression, while loss of MexAB-OprM was associated with increased expression of MexEF-OprN, also indicative of an inverse correlation between MexAB-OprM and MexEF-OprN expression. Still, the increases in MexCD-OprJ and MexEF-OprN failed to compensate for the loss of MexAB-OprM with respect to antibiotic resistance. Nonetheless, these data suggest that the overall complement of these MDR efflux systems is monitored and that alterations in the level of one efflux system may effect compensatory changes in the levels of the others.

Evidence for a leukotriene A4 hydrolase in Xenopus laevis skin exudate.

Leukotriene A4 hydrolase is a cytosolic metalloenzyme of the arachidonic acid biosynthetic pathway responsible for leukotriene A4 conversion into leukotriene B4. In addition to its epoxide hydrolase properties, this enzyme exhibits an aminopeptidase activity which was used as an assay to monitor the purification of a novel form of leukotriene A4 hydrolase from Xenopus laevis skin exudate. This 70 kDa, secreted, form of leukotriene A4 hydrolase was identified by immunochemical cross-reactivity with anti-human leukotriene A4 hydrolase antibodies and by its capacity to convert leukotriene A4 into leukotriene B4. Moreover this enzyme produced a second metabolite which could be the leukotriene B4 isomer 5S,12R-dihydroxy-6,10-trans-8,14-4-cis-eicosatetraenoic acid, previously shown by Strömberg et al. (Eur.J. Biochem. 238 (1996) 599-605) to be formed by incubation of the leukotriene A4 with amphibian tissue extracts. Partial amino acid sequencing of peptides generated by endolysin C fragmentation of the purified enzyme confirmed the presence, in X. laevis skin secretions, of a related but distinct form of leukotriene A4 hydrolase which is likely to be responsible for the production of these eicosanoid metabolites of leukotriene A4.

Successes and failures in the tropical bont tick eradication campaigns in the French antilles.

The Amblyomma variegatum eradication campaigns, based on three phases and a 5-year program, as in other islands of the Caribbean, started in the French Antilles in April 1994 with various financial inputs. The progress of the campaigns in the two islands of Guadeloupe and Martinique contrast sharply. Owing to a shortage and inadequacy of results with regard to the initial objectives, particularly in organization, communication efforts, cattle identification, and application of acaricides on livestock, the European Community which was the most important donor, did not support the Guadeloupean program in 1996 and 1997. This induced a deep crisis in the local sanitary organization, which has the responsibility for the execution of the project, and the almost total interruption of acaricide treatments in Guadeloupe and its dependencies (Marie-Galante, St Martin, Désirade). In Martinique on the contrary, a well-defined organization, communication strategy, and personnel training effort resulted in a generalized census of livestock owners. Identification of cattle increased dramatically in number and the systematic treatment of livestock started in satisfying conditions. It is too early to anticipate on the final result of the campaign, but it is clear that a longer period of time than previously planned, will be necessary to achieve the program. If this prolongation is accepted, it may allow Guadeloupe to take part again in the campaign, a condition absolutely necessary for its regional success.

Attempts to feed Amblyomma variegatum ticks on artificial membranes.

Feeding jars were used to feed nymphs of Amblyomma variegatum on blood of goats or cattle. Sterile blood was collected daily or weekly (kept at 4 degrees C or frozen until use), with addition either of heparin alone or of heparin and antibiotics/fungicide or of heparin, adenosine triphosphate and glutathione. Membranes were made of a thin (0.12-0.32 mm) film of silicone mastic. Blood in the jars was replaced twice a day, and reached a temperature of 39 degrees C in a waterbath before it became available to the ticks. Attachment of nymphs was stimulated by dropping on the membrane fresh goat hair and squamae collected close to prefed males, skin washing and natural pheromone extracts. Using these devices, attachment of nymphs is rapid and intense (68%). Their body mass when engorged and the molting success, were lower than that of naturally fed ticks. Furthermore, the proportion of engorging ticks was usually much less and the length of the blood meal was much longer than of naturally fed ticks. The best results were obtained with fresh goat blood or cattle blood with antibiotics. Further developments are needed before this method can be used routinely.