Natural transmission of Pneumocystis carinii in nonimmunosuppressed animals: early contagiousness of experimentally infected rabbits (Oryctolagus cuniculus)

Abstract

Airborne transmission of Pneumocystis carinii has been established, but the infective form and the sources of infection remain unknown. Animal models for studies of P. carinii have previously been limited to immunosuppressed rodents; however, this study was performed with nonimmunodepressed P. carinii-free rabbits. This study was aimed at determining (i) the delay between inoculation of animals (day zero [D0]) and the onset of contagiousness and (ii) the end of contagiousness of these animals (donors). Five-week-old rabbits were used as contact animals and were housed with the donors. The cohabitation periods were for 4 or 5 days from D0 to D4, D4 to D8, D8 to D13, D13 to D18, and D18 to D22. The highest parasite burdens were observed in contact animals housed with donors from D8 to D13 or D13 to D18. This period (8th to 18th day following the day of inoculation of donors) might correspond to the highest phase of contagiousness of donors.

Immunohistochemical study of Pneumocystis carini infection in pigs: evaluation of Pneumocystis pneumonia and a retrospective investigation

“…The results indicated that P carinii was transmitted between pigs by aerosol, but not vertically, although the infection was demonstrated in young suckler pigs. The airborne transmission of P carinii has been reported in rats, rhesus macaques and rabbits (Hughes 1982, Vogel and others 1993, Cere and others 1997). There was no transmission via the placenta even in heavily infected mice (Ito and others 1991).…”

Assessment of Pneumocystis species carriage in captive primates

“…However, the presence of Pneumocystis species DNA in twin stillborn marmosets ( Callithrix jacchus ) suggested that vertical transmission of Pneumocystis species may occur in non‐human primates. This mode of transmission was ruled out in mice (Ito and others 1991) but is suspected in human beings (Mortier and others 1995) and has been proved in rabbits (Ceré and others 1997).…”

“…The lungs were finely minced, homogenised by crushing and subjected to sequential membrane filtration (Ceré and others 1997). The final filtrates were used for direct examination and DNA extraction.…”

Bacterial and Pneumocystis Infections in the Lungs of Gene-Knockout Rabbits with Severe Combined Immunodeficiency

“…Although less commonly used than rodents, studies of rabbits infected by P. oryctolagi have revealed some distinct features. Compared to rodents, healthy rabbits can develop relatively heavy Pneumocystis infection either spontaneously at weaning or following cohousing with infected rabbits ( 19 , 20 ). This spontaneous, natural infection is usually resolved within 3–4 weeks.…”