Search PubMed⌕ Search

Biomedical subjects

L Belloy

Publications and source records attributed to L Belloy.

6 recordsLinked to original sources
PubMed2005

Dielectric monitoring of growth and sporulation of Bacillus thuringiensis.

On-line permittivity and optical density measurements have been used to monitor biomass concentration and sporulation status during growth of a spore-forming bacterium, Bacillus thuringiensis, in fed-batch culture. The correlation between permittivity, optical density and other observations showed three distinct phases of growth: growth itself, transition and sporulation. The permittivity variations during the transition and sporulation phases could be related to the sporulation development: the evolution pattern of the ratio of optical density to permittivity was representative of the culture state, and during the sporulation phase, a permittivity index could be build to measure the extend of spore liberation.

Absorption↗
PubMed2002

Infectious keratoconjunctivitis of ibex, chamois and other Caprinae.

Infectious keratoconjunctivitis (IKC) caused by Mycoplasma conjunctivae is a highly contagious ocular infection which is common in domestic sheep and goats. In the European Alps, IKC is often observed in Alpine chamois (Rupicapra r. rupicapra) and in Alpine ibex (Capra i. ibex), but the disease has also been described in other wild Caprinae in the Pyrenees and in New Zealand. The infection is characterised by inflammation of the conjunctiva and cornea, and in the most advanced stages, the cornea is opaque or even perforated. In IKC outbreaks in chamois and ibex, spontaneous recovery is the most prevalent outcome of the disease. However, mortality can occasionally reach 30%. Recent studies in eastern Switzerland indicated that M. conjunctivae infection is not self-maintained in chamois. In contrast, the disease is endemic and self-maintained in the domestic sheep population. Spillover of the agent from sheep living in proximity during summer may be the origin of point-source epidemics in wild Caprinae. Flies are likely to play a central role in interspecific transmission of M. conjunctivae on alpine meadows. When outbreaks of IKC occur in wildlife, a special effort should be made to avoid unnecessary human disturbance in affected areas. However, animals presenting irreversible ocular lesions should be shot by professional gamekeepers to prevent suffering. Prevention of IKC in wild Caprinae should focus on preventing the spillover of M. conjunctivae from livestock. However, studies are required to evaluate the distribution of M. conjunctivae infection in domestic sheep in several countries and to assess the risk of IKC spillover from domestic animals to wildlife. In addition, immunological studies should be performed to develop tools which could lead to the control of M. conjunctivae infection in domestic sheep.

Animals↗
PubMed2001

Mycoplasma conjunctivae infection is self-maintained in the Swiss domestic sheep population.

Bacteriological and serological investigations were performed to assess whether the domestic sheep population is a reservoir of Mycoplasma conjunctivae in Switzerland. Among a sample of 69 sheep showing clinical signs of infectious keratoconjunctivitis (IKC) in three Swiss cantons, M. conjunctivae was identified 53 times (76.8%). A commercially prepared indirect ELISA was used to detect M. conjunctivae antibodies in 674 sera of adult sheep. We analysed a stratified random sample of 123 sheep herds from 25 out of the 26 Swiss cantons. At least one positive animal was detected in 89.4% of the herds. In positive herds (n=110), 57.1% of the individual animals tested positive. To assess the importance of sheep's age in the spread of M. conjunctivae, 209 sera of adult sheep and 93 lamb sera among eight sheep herds were analysed using the indirect ELISA. Seroprevalence in 2-6-month-old lambs was 50.5%, indicating that the IKC agent is spread in sheep flocks during raising. Lambs experimentally infected with M. conjunctivae carried the agent for 8 and 23 weeks, respectively, depending on the strain used for challenge. We conclude that the M. conjunctivae-infection is endemic and self-maintained in the domestic sheep population in Switzerland.

Animals↗
PubMedDate not supplied

Detection of specific Mycoplasma conjunctivae antibodies in the sera of sheep with infectious keratoconjunctivitis.

The serological cross reactions between Mycoplasma conjunctivae, the etiological agent of infectious keratoconjunctivitis (IKC), and the antigenetically and phylogenetically closely related Mycoplasma ovipneumoniae, which is often found in sheep, were analysed. Cross reacting antigens were identified using sera from sheep with IKC and from sheep of herds known to be free of IKC, as well as rabbit hyperimmune serum specific to the two Mycoplasma species. Cross reactions were predominantly due to the strongly antigenic proteins of 42 kDa and 83 kDa. Serospecific antigens of M. conjunctivae could be separated from cross-reacting antigens by the extraction of Tween 20-soluble membrane proteins. The Tween 20-extracted proteins of the M. conjunctivae strain HRC/581T were used for the development of an indirect ELISA test. This ELISA test was shown to be a useful serological method for the diagnosis of M. conjunctivae infections and to identify infected sheep herds.

Animals↗