Signalment:  

Placenta from an aborted meat goat fetus (Capra hircus).Increased late-term abortions were reported in the herd. We received a placenta only on the first submission and 2 fetuses with placentas later.


Gross Description:  

The fetal tissues were unremarkable and the placentas had diffuse rough thickening of the cotyledons and multifocal to coalescing pale, slightly raised foci and plaques on the intercotyledonary membranes (Fig 1).


Histopathologic Description:

There is diffuse cotyledonary necrosis with intralesional, intracellular (intratrophoblastic) minute, basophilic organisms and multifocal intercotyledonary necrotizing placentitis. Intact trophoblasts laden with the numerous intracytoplasmic bacteria are somewhat more evident on the intercotyledonary placenta.


Morphologic Diagnosis:  

Necrotizing placentitis, due to Coxiella burnetti (Q Fever).


Lab Results:  


Culture: No Brucella sp. or other significant bacteria from the placenta or fetus (4+ alpha Streptococcus sp. and 4+ E. coli in the abomasal fluid and placenta). Leptospira F.A.: Negative on fetal kidneys. Chlamydia (Chlamydophila) PCR: Negative. Coxiella burnetti immunohistochemistry: Positive (done at UC Davis).


Condition:  

Coxiella burnetti


Contributor Comment:  

Myriad intracellular minute bacteria are in the surface trophoblasts of the cotyledons and on the intercotyledonary chorion with essentially diffuse necrosis that spares only limited sections of the intercotyledonary chorion. Ruminants, especially sheep and goats, are susceptible to Coxiella burnetti placentitis and abortion and humans are very susceptible to infection. The organisms are acid-fast,(8) as were ours, with a diffuse granular red staining of the infected trophoblast cytoplasm (Fig. 2). They also stain with Gimenez as intracellular clusters of coccobacilli or thin rods, whereas Chlamydophila are uniformly round.(7,8) Our Giemsa stain also demonstrates that the swollen trophoblasts were filled with granular organisms (Fig. 3). Toxoplasmosis was ruled out by the minute size of the organisms and lack of involvement of the brain and other internal fetal tissues and lack of reaction with PAS. Fetal lesions are generally lacking with Q fever, although the agent can be found in the fetal tissues by PCR (10) and about 10% of the fetuses may have multifocal subacute or histiocytic inflammation.(7) Chlamydophila would be the main consideration, and our PCR for it was negative. The causative agent for that has been renamed from Chlamydia psittaci serotype 1 to Chlamydophila abortus. 

Coxiella, Brucella, and Chlamydophila infections in sheep and goats cause both cotyledonary and intercotyledonary necrosis (3,4,8) and all 3 agents target the intracellular fetal trophoblast cells.(10) Campylobacter infection causes similar lesions with necrotic inflammation also being in the fetal tissues.(4,5) Campylobacteriosis only affects the cotyledons in cows.(3)

One survey in France (8) found that infected or carrier cows and goats generally shed Coxiella in their milk and sheep mostly in vaginal secretions and feces. Since human infection is generally by aerosol, this might explain why humans are at greater risk from contact with sheep. This study did not find a correlation between recent parturition and shedding of organisms.

A PCR survey (5) of milk goat abortions on the island of Sardinia found 82.7% negative for an infectious agent and 16.3% positive with the results as below from 23 caprine fetuses and 8 placentas:



Goats may abort with Coxiella infection in 2 consecutive pregnancies although they have antibodies, so there may not be protective immunity after the first infection and a carrier state is possible.(1) Another survey found 9% of the goat abortions being due to Coxiella infection, but lesions were usually limited to the placenta and many submissions did not have the placenta.(7)


JPC Diagnosis:  

Chorioallantois: Placentitis, necrotizing and suppurative, subacute, multifocal, marked, with vasculitis and intratrophoblastic coccobacilli.


Conference Comment:  

The contributor provides a succinct review of this entity and the differential diagnosis. Conference participants noted the foamy appearance of cells containing the Coxiella burnetti organism in this case, which is characteristic. Both Coxiella burnetti and Chlamydophila abortus stain positively with the modified acid fast stain or by the Gimenez method, which differentiates them from Brucella abortus and Campylobacter species. Coxiella burnetti and Chlamydophila abortus are morphologically distinct; the former are thin, pleomorphic, rod-shaped structures, while the elementary bodies in Chlamydophila abortus infection are round and smaller.(4) The pleomorphism of the Coxiella organism is attributed to the fact that when it replicates by binary fission, three distinct developmental forms result: spore, small cell variant, and large cell variant.(2)

While both organisms can cause both cotyledonary and intercotyledonary necrosis, the gross lesions of Chlamydophila infection affect the cotlyledons and intercotyledonary regions in roughly equal proportions, while the placental lesions in Coxiella burnetti infection are most prominent in the intercotyledonary region. Both organisms can cause vasculitis in the placenta, although it is characteristically more marked in Chlamydophila abortion.(4)


References:

1. Berri M, Rousset E, Champion JL, Russo P, Rodolakis, A: Goats may experience reproductive failures and shed Coxiella burnetti at two successive parturitions after a Q fever infection. Res Vet Sci 83:47-52, 2007
2. Brogden KA: Cytopathology of pathogenic prokaryotes. In: Ultrastructural pathology: the comparative cellular basis of disease, ed. Cheville NF, 2nd ed., p. 476, Wiley-Blackwell, Ames, IA, 2009
3. Buergelt CL: Color Atlas of Reproductive Pathology of Domestic Animals. Mosby, St. Louis, MO, pp. 179-187, 1997
4. Kennedy PC, Miller RB: The female genital system. In: Pathology of Domestic Animals, eds. Jubb KVF, Kennedy PC, Palmer N, 4th ed., vol. 3, pp. 396-419, Academic Press, San Diego, CA, 1993
5. Ladds PW, We F-M, Chang W-F, Shyu J-J: A Color Atlas of Veterinary Reproductive Pathology. Pig Research Institute, Taiwan, pp. 292-294, 297-298, 1997
6. Masala G, Porcu R, Daga C, Denti S: Detection of pathogens in ovine and caprine samples from Sardinia, Italy, by PCR. J Vet Diagn Invest 19:96-98, 2007
7. Moeller RB: Causes of caprine abortion: diagnostic assessment of 211 cases (1991-2998), J Vet Diag Invest 13:265-270, 2001
8. Moore JD, Barr BC, Daft BM, OConnor MT: Pathology and diagnosis of Coxiella burnetti infection in a goat herd. Vet Pathol 28:81-84, 1991
9. Rodolakis A, Berri M, H+�-�chard C, Caudron C, et al: Comparison of Coxiella burnetti infection in milk of dairy bovine, caprine, and ovine herds. J Dairy Sci 90:5352-5360, 2007
10. S+�-�nchez J, Souriau A, Buend+�-�a AJ, et al: Experimental Coxiella burnetti infection in pregnant goats: a histopathological and immunohistochemical study. J Comp Path 135:108-115, 2006


Click the slide to view.


1-1. Placenta


1-2. Placenta


1-3. Placenta


1-4. Placenta


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