Avian chlamydiosis is a disease caused by a parasitic bacterium called C. psittaci which affects more than 465 species of domestic, farmed or wild birds. This pathogen is transmissible to humans and can cause an acute form of pneumonitis which can be fatal in vulnerable people when not diagnosed and treated in time. People in direct contact with birds, such as farm staff, slaughterhouses or veterinarians, are the most exposed.
The healthy bearing of C. psittaci by birds and poultry is very common in the poultry sector.
Recent work carried out by the NRL has led to the identification of new species of Chlamydia, particularly in chickens, pigeons or the sacred ibis.
A new strain of Chlamydia discovered in the sacred ibis
The African sacred ibis has been imported into many zoos around the world. In the 90s, a group of ibises escaped from an animal park located in Brittany. Very invasive, this species then multiplied rapidly and settled along the Atlantic coast. This population, which numbered more than 5,000 individuals, represented a major ecological problem for native animal biodiversity, but also potentially a health problem as a reservoir of pathogens.
As these ibises had been seen in contact with farmed ducks in which the prevalence of C. psittaci is important, the NRL, in partnership with a team from Nantes, carried out a study to find out if these wild birds might be carriers of the pathogenic bacteria and if they might constitute a risk for open-air farms.
Unexpected discovery of a new species
The analyzes carried out on 70 sacred ibises showed that 8 individuals were carriers of Chlamydiaceae. Against all odds, only one of them was carrying C. psittaci, the pathogen classically isolated from birds. The other 7 housed a Chlamydia with atypical characters. In collaboration with an American team and a German team, the complete sequencing of the genome of the incriminated strain, as well as electron microscopy pictures, might be carried out and made it possible to affirm that these Chlamydia atypical corresponded to a new species, baptized C. ibidis.
To date, no evidence has been provided regarding the pathogenicity of C. ibidis. It is now necessary to carry out additional studies to deepen the knowledge of this new species.
Questions to be clarified by ANSES
This discovery raises questions that remain to be elucidated to this day. First of all, it would be interesting to determine the geographical origin of the infection by these new Chlamydia : Were sacred ibises infected in Africa, their region of origin, or in France following their importation? Is this bacterium present in the environment? Can it infect other species of birds, or even other animals? Finally, it is necessary to monitor the zoonotic nature of this new species (transmission of the bacteria to humans), which, if proven, might pose a public health problem. The answers to these various questions will enable ANSES to conduct a risk assessment concerning this new species.
