Q fever is a zoonosis caused by the obligate intracellular bacterium Coxiella burnetii, classified in the Coxiellaceae family in the order Legionellales of the gamma subdivision of Proteobacteria.6 Unlike the family Rickettsiaceae, C. burnetii is highly resistant to physical and chemical agents, and that leads to the suggestion that its developmental cycle consists of vegetative and spore-like forms.12 In animals the main clinical manifestation is abortion in domestic ruminants and other animals.16 A wide range of hosts can be infected without showing any clinical signs,2 and therefore cats, dogs, rabbits, birds, etc., can also serve as a reservoir.5,9-11,13 Coxiella burnetii is excreted in milk, feces, urine, and in very high numbers in the amniotic fluid, placenta, and fetal membranes of parturient animals.1,4,8,14,15 Animals may shed infectious material long after abortion.3
Acute Q fever in marine mammals has not been reported in the literature, but a pathologic examination of a Pacific harbor seal (Phoca vitulina richardii) revealed a placentitis due to an infection with C. burnetii.7 In early 2004, Tierpark Hagenbeck maintained 1.2 South American sea lions (Otaria byronia) and 3.7 South American fur seals (Arctocephalus australis). In March, a female fur seal was killed when the breeding male tried to mate her. Postmortem examination revealed the presence of a fetus, foci of necrotizing placentitis, and congestion of multiple organs. Because there had been some stillbirths at our park previously, tissue samples were submitted to determine the possible presence of C. burnetii, and Coxiella-specific deoxyribonucleic acid (DNA) sequences using polymerase chain reaction (PCR) were confirmed.
In May, a second female fur seal was drowned by the male. This female had a fetus in her uterus, congestion of multiple organs, and a hemorrhagic, necrotic placenta. PCR evaluation also recovered Coxiella DNA. Two weeks later, an abortion occurred in one of the sea lion pups. This pup had congestion in various organs as well as signs of hemorrhage and necrosis in the placenta. This animal was also confirmed to be Coxiella positive by PCR. In early July, another fur seal was born dead. Apart from congestion in different organs, no pathologic lesions were found, and no Coxiella DNA was detected. A week later another sea lion had a stillbirth. The placenta in this animal showed signs of a placentitis with no pathologic lesions in the baby and no Coxiella evidence. Unfortunately, the placenta was not examined for Coxiella.
1. Abinanti, F.R., E.H. Lennette, J.F. Winn, and H.H. Welsh. 1953. Q fever studies. XVIII. Presence of Coxiella burnetii in the birth fluids of naturally infected sheep. Am. J. Hygiene. 58:385–388.
2. Babudieri, B. 1959. Q fever: A zoonosis. Advances Vet. Sci. Comp. Med. 5:81–181.
3. Berri, M., A. Souriau, M. Crosby, C.D. Lechopier, and A. Rodolakis. 2001. Relationship between the shedding of Coxiella burnetii clinical signs and serological responses of sheep. Vet. Rec. 148:502–505.
4. Grist, N.R. 1959. The persistence of Q fever infection in a dairy herd. Vet. Rec. 71:839–841.
5. Kosatsky, T. 1984. Household outbreak of Q-fever pneumonia related to a parturient cat. Lancet. 2:1447–1449.
6. Labrenz, M., and P. Hirsch. 2003. The genus Coxiella. In: Garrity, G., D.R. Boone, and R.W. Castenholz, eds. Bergey’s Manual of Systematic Bacteriology. Springer-Verlag, New York, NY.
7. Lapointe, J.M., F.M. Gulland, D.M. Haines, B.C. Barr, and P.J. Duignan. 1999. Placentitis due to Coxiella burnetii in a Pacific harbor seal (Phoca vitulina richardsi). J. Vet. Diagn. Invest. 11:541–543.
8. Luoto, L., J.F. Winn, and R.J. Huebner. 1952. Q fever in Southern California. XIII. Vaccination of dairy cattle against Q fever. Am. J. Hygiene. 55:190–200.
9. Marrie, T.J. 1990. Epidemiology of Q fever. In: Marrie, T.J., ed. Q Fever. Vol. I: The disease. CRC Press, Boca Raton, FL. Pp. 49–70.
10. Marrie, T.J. 1990. Q fever—A review. Can. Vet. J. 31:555–563.
11. Maurin, M., and D. Raoult. 1999. Q fever. Clin. Microbiol. Rev. 12:518–553.
12. McCaul, T.F., and J.C. Williams. 1981. Developmental cycle of Coxiella burnetii: Structure and morphogenesis of vegetative and sporogenic differentiations. J. Bacteriol. 147:1063–1076.
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14. Stoker, M.G.P., and B.P. Marmion. 1955. The spread of Q fever from animals to man: The natural history of a rickettsial disease. Bull. World Health Org. 13:781–806.
15. Welsh, H.H., E.H. Lennette, F.R. Abinanti, and J.F. Winn. 1953. Q fever in California: IV. Occurrence of Coxiella burnetii in the birth fluids of naturally infected sheep. Am. J. Hygiene. 58:358–388.
16. Woldehiwet, Z., and I.D. Aitken. 1993. Coxiellosis (Q fever). In: Woldehiwet, Z., and M. Ristic, eds. Rickettsial and Chlamydial Diseases of Domestic Animals. Pergamon Press, Oxford, GB. Pp. 131–151.