Chlamydial infection in a colony of captive koalas

Abstract

Forty three koalas in a captive colony were investigated for the presence of Chlamydia psittaci infection and associated disease. Swabs were taken from conjunctivae and urogenital sites for cell culture isolation of C psittaci and for cytological examination (direct smears) for chlamydial inclusions and evidence of inflammation. On the basis of cell culture isolation, 28 samples from 25 koalas were positive for C psittaci (that is, infected). Three koalas were positive from both sites, 5 from conjunctivae alone and 17 from urogenital sites alone. Seven of the 8 koalas with positive conjunctival swabs had overt signs of conjunctivitis, but only 3 of the 20 koalas with positive urogenital swabs had overt signs of 'wet bottom' (continual urine soiling due to cystitis) or purulent discharge. However, 5 of the 20 with positive urogenital swabs had past episodes of 'wet bottom'. Moreover, examination of direct cytological smears showed evidence of inflammation (neutrophils) in 7 of 8 koalas with positive conjunctival swabs and 17 of 20 with positive urogenital swabs. Chlamydial inclusions were rarely identified with surety on direct cytological smears. In the 18 koalas without chlamydia, one had overt conjunctivitis while 2 had past episodes of conjunctivitis. The koala with conjunctivitis at the time of sampling had a prior history of 'wet bottom'. Examination of direct cytological smears revealed 2 of the chlamydial negative koalas had high numbers of neutrophils in urogenital smears. It was concluded that C psittaci infection may cause overt or sub-clinical disease, with the former developing when the koalas were stressed through management procedures or concomitant disease.

Preliminary Characterisation of Tumor Necrosis Factor Alpha and Interleukin-10 Responses to Chlamydia pecorum Infection in the Koala (Phascolarctos cinereus)

“…Chlamydia pecorum is the main aetiological agent of infectious disease in the koala with studies reporting around 60–98% prevalence of chlamydial infection in certain free range koala populations [9], [10], [11], [12]. C. pecorum infection in koalas has been associated with cystitis, proliferative conjunctivitis and chronic, fibrotic disease of the urogenital tract leading to infertility and death [13], [14], [15], [9], [16], [12].…”

ORIGINAL ARTICLE: A Multi‐Subunit Chlamydial Vaccine Induces Antibody and Cell‐Mediated Immunity in Immunized Koalas (Phascolarctos cinereus): Comparison of Three Different Adjuvants

“…Chlamydia continues to be the most important infectious disease affecting the koala ( Phascolarctos cinereus ) 1–4 . Together with habitat destruction, because of urban development in particular, these combined threats mean that many koala populations in Australia are under significant threat of collapse.…”

“…Ocular infections cause keratoconjunctivitis leading to blindness 6,7 . Rhinitis and pneumonia are associated with respiratory infections and urinary tract infections cause cystitis and continual urine soiling or ‘wet bottom’ 2 . Infections of the genital tract can cause severe inflammation and fibrosis resulting in cystitis and infertility 1 .…”

Sexually transmitted diseases in polygynous mating systems: prevalence and impact on reproductive success

“…Moreover, it is only recently appreciated that STDs are much more abundant in animal populations than previously thought (Lockhart et al 1996) and that such diseases may be an important component of population regulation. For example, some koala populations are endangered because of the high prevalence of chlamydial infections (Can¢eld et al 1991) and in humans the AIDS epidemic in Africa has the potential to cause population growth rates to become negative over the next few decades (May et al 1988;.…”