Persistence and Significance of Chlamydia trachomatis in the Housefly, Musca domestica L.

Trachoma is the leading cause of infectious blindness worldwide. Ocular infection by the obligate intracellular pathogen, Chlamydia trachomatis, causes the eyelashes to turn in and scratch the cornea, leading to blindness if left untreated. The disease is most prevalent in poor, rural communities that lack the infrastructure for basic hygiene, clean water, and proper sanitation. Infection is often spread through infected clothes, contaminated hands, and face seeking flies. The goal of this research was to understand the biological role of Musca domestica flies in the transmission of C. trachomatis. PCR, tissue culture, and immunofluorescence microscopy were used to determine the presence, viability, and the anatomical location of C. trachomatis within the digestive tract of M. domestica. Flies were fed with C. trachomatis and then harvested at various time intervals after feeding. The data confirmed the presence of C. trachomatis DNA and viable elementary bodies (EBs) in fly crops, up to 24 h postfeeding. C. trachomatis DNA was also isolated from the upper portions of the alimentary tract of flies up to 48 h postfeeding. In addition, DNA was isolated from the regurgitation material from fly crops up to 12 h postfeeding. The viability of isolated C. trachomatis EBs was repeatedly confirmed between 12 and 48 h and up to 7 days in ex vivo crops stored at room temperature. Our data suggest that eye-seeking flies such as M. domestica can ingest C. trachomatis during regular feeding. Because M. sorbens does not occur in continental United States, we did not use it in any of our studies. These data also confirm, for the first time, that ingested chlamydia remains viable inside the flies for 24-48 h postfeeding. We further show that these flies can regurgitate and transmit the trachoma agent at their next feeding. We believe that these findings reveal an opportunity for efficient intervention strategies through fly vector control, especially as we near new target date for global elimination of trachoma.

Effects of water-filtered infrared A and visible light (wIRA/VIS) radiation on heat- and stress-responsive proteins in the retina and cornea of guinea pigs.

Water-filtered infrared A and visible light (wIRA/VIS), shown to reduce chlamydial infections in vitro and in vivo, might represent an innovative therapeutic approach against trachoma, a neglected tropical disease caused by ocular infection with the bacterium C. trachomatis. In this in vivo study, we assessed the impact of wIRA radiation in combination with VIS (wavelength range 595-1400 nm, intensity 2100 W/m2) on the retina and cornea in a guinea pig animal model of inclusion conjunctivitis. We investigated the effects 19 days after wIRA/VIS irradiation by comparing a single and double wIRA/VIS treatment with a sham control. By immunolabeling and western blot analyses of critical heat- and stress-responsive proteins, we could not detect wIRA/VIS-induced changes in their expression pattern. Also, immunolabeling of specific retinal marker proteins revealed no changes in their expression pattern caused by the treatment. Our preclinical study suggests wIRA/VIS as a promising and safe therapeutic tool to treat ocular chlamydial infections.

[Experimental trachoma]. / Le trachome expérimental.

During half a century, the agent of trachoma could be mainly demonstrated by inoculation to the conjunctiva of animals; by this mean the cycle of the agent could be revealed. There was a huge progress when T'ANG for these studies inoculated embryonated chicken eggs. However, experimentally infected animals are used at present time not only in trachome countries where do not exist laboratories: monkeys, guinea pigs, rabbits, rats and mice allow modern studies of chlamydial infection. Monkeys living in the countries where trachoma is endemic were selected because of their cheapness (orangoutan in Java, macaques in Northern Africa and in Taïwan, baboons in Africa). The monkeys selected by American workers are coming from South America. First pioneers (NICOLLE, CUENOD and NATAF, PAGES, JULIANELLE) have demonstrated the infectivity of animals and the place of the agent of trachoma on taxonomic point of view. As PAGES, we have demonstrated that infection could be regularly provoked when inoculating macaques; moreover a pannus could appear when adding hydrocortison drops or when infiltrating the cornea with tuberculin. Cultures of WEEKS bacilli were introduced in the eyes of trachomatous animals; we could observe an aggravation of the disease. If biology of trachoma is better known at present time, experimental trachoma is until now fundamentally important. It permits immunological studies especially for the purpose of vaccination; one can check terapeutical means for instance antibiotics; studies are performed to demonstrate cross immunizations or enhancement of defence (with levamisole). Experimental trachoma is hitherto and again for a long time commonly requested for the study of trachoma.

Micro cell culture method for isolation of Chlamydia trachomatis.

Presterilized mictotiter plates (96 wells) with BHK-21 cells on 5-mm cover slips were successfully used for cell culture isolation of trachoma from 15 infected conjunctival scrapings.