Background Outbreaks of a Haemorrhagic Septicaemia (HS) like disease causing
large mortalities in camels (Camelus dromedarius) in Asia and in Africa have
been reported since 1890. Yet the aetiology of this condition remains elusive.
This study is the first to apply state of the art molecular methods to shed
light on the nasopharyngeal carrier state of Pasteurellaceae in camels. The
study focused on HS causing Pasteurella multocida capsular types B and E.
Other Pasteurellaceae, implicated in common respiratory infections of animals,
were also investigated. Methods In 2007 and 2008, 388 nasopharyngeal swabs
were collected at 12 locations in North Kenya from 246 clinically healthy
camels in 81 herds that had been affected by HS-like disease. Swabs were used
to cultivate bacteria on blood agar and to extract DNA for subsequent PCR
analysis targeting P. multocida and Mannheimia-specific gene sequences.
Results Forty-five samples were positive for P. multocida genes kmt and psl
and for the P. multocida Haemorrhagic Septicaemia (HS) specific sequences
KTSP61/KTT72 but lacked HS-associated capsular type B and E genes capB and
capE. This indicates circulation of HS strains in camels that lack established
capsular types. Sequence analysis of the partial 16S rRNA gene identified 17
nasal swab isolates as 99% identical with Mannheimia granulomatis,
demonstrating a hitherto unrecognised active carrier state for M. granulomatis
or a closely related Mannheimia sp. in camels. Conclusions The findings of
this study provide evidence for the presence of acapsular P. multocida or of
hitherto unknown capsular types of P. multocida in camels, closely related to
P. multocida strains causing HS in bovines. Further isolations and molecular
studies of camelid P. multocida from healthy carriers and from HS-like disease
in camels are necessary to provide conclusive answers. This paper is the first
report on the isolation of M. granulomatis or a closely related new Mannheimia
species from camelids