First Identification ofChlamydia psittaciin the Acute Illness and Death of Endemic and Endangered Psittacine Birds in Mexico

Abstract

A mortality episode of endemic and endangered psittacine birds from the genera Ara and Amazona occurred during January 2015. The birds were housed in a management unit for wildlife conservation that receives wild-caught birds from illegal trade. In total, 11 (57%) adult birds of different origins that shared these accommodations died. Only four of them were sent for diagnosis. The main lesions found at necropsy were consistent with those described previously for avian chlamydiosis; the presence of Chlamydiaceae was confirmed through immunofluorescence and amplification with further sequencing of the 16S ribosomal RNA gene by using hepatic tissue. Due to the lack of specific diagnostic tools on primary psittacine diseases, the pathogenic effects of systemic, respiratory, or enteric infections with high mortality rates remain unknown in Mexico. In this study, specific molecular identification of avian chlamydiosis was performed using a nested PCR on liver tissues, as well as choanal and cloacal swab samples, confirming the presence of Chlamydia psittaci in all of them. In addition, it was possible to obtain the ompA gene sequence from processed clinical samples, thereby allowing us to determine that the A genotype was affecting these birds. Although this genotype is the most commonly found worldwide in psittacine birds, this case report describes the first avian chlamydiosis outbreak affecting critically endangered and endemic psittacines subjected to reintegration programs in Mexico. Consequently, this study demonstrates the necessity of more exhaustive biosecurity strategies because other pathogens may be present and should be assessed, especially in highly threatened birds, before releasing them into their habitats.

A Chlamydia psittaci Outbreak in Psittacine Birds in Sardinia, Italy

“…However, there are several prevention measures that can be adopted to mitigate the incidence of chlamydiosis; for example, the use of protective clothing and masks, correct disposal of infected material, quarantine of imported birds, adequate disinfection of the potentially contaminated areas because C. psittaci can persist for prolonged periods in the environment [ 29 ]. In some cases, pet shop owners include tetracycline in the drinking water of birds for sale (especially for psittacine birds such as parrots) to keep them healthy until sold [ 10 ]. However, this wrong practice could often generate resistant strains of bacteria that may become established in the psittacine birds [ 30 ].…”

“…The transmission of the infectious agent among birds occurs by direct contact, through the release of nasal excretions or contact with contaminated faeces and concerns the most susceptible birds [ 10 ]. In birds, the disease can manifest itself in acute, subacute, and chronic forms with symptoms including anorexia, diarrhea, lethargy, weight loss, and sometimes it presents only mucopurulent or serious oculonasal discharge.…”

A Review of Chlamydial Infections in Wild Birds

“…For example, high rates of C. psittaci infection have been found in healthy captive Amazon parrots ( Amazona genus) in breeder collections [ 106 ] but the same genus has also suffered mortality rates of up to 97% when infected under stressful conditions [ 107 ]. Indeed, in most cases where C. psittaci has caused acute death or severe disease, for parrots at least, affected individuals were already stressed or immunocompromised, with many having recently been captured from the wild [ 107 , 115 ] or being co-infected with other pathogens, such as beak and feather disease virus (BFDV) [ 32 ].…”

“…The same may be true for other Chlamydiales species, although their pathogenicity remains to be investigated. Chlamydial infection in certain avian populations may therefore be of conservation concern, particularly in hosts such as parrots, which are one of the most highly threatened bird orders [ 59 ], are known to suffer frequent C. psittaci infections [ 7 , 33 ] and can subsequently suffer high mortality [ 107 , 115 ]. In parrots and other birds, small, highly threatened populations that may have lost endemic pathogens may be particularly at risk of infection via pathogen spill-over from sympatric species, as suggested recently with BFDV in the critically endangered orange-bellied parrot ( Neophema chrysogaster ) [ 119 ].…”