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Arquivo Brasileiro de Medicina Veterinária e Zootecnia

Print version ISSN 0102-0935On-line version ISSN 1678-4162

Arq. Bras. Med. Vet. Zootec. vol.54 no.4 Belo Horizonte July/Aug. 2002 




Malignant oedema associated with navel infection in a Merino lamb

[Edema maligno associado com infecção do umbigo em um cordeiro Merino]


W.E. Morris,1, F.A. Uzal1*, M. Paramidani2

1Animal Health Unit, Tthe National Institute of Agricultural Technology, Bariloche, Argentina
Veterinaria Alvear, Esquel, Argentina


Recebido para publicação em 3 de agosto de 2001
Recebido para publicação, após modificações, em 5 de março de 2002
*Present address of correspondence author:
California Animal Health and Food Safety Laboratory
105 W. Central Ave
San Bernardino, CA 92408, USA



Although a few authors have mentioned navel infections as a cause of perinatal lamb mortality (Haughey, 1993; Dennis, 1974), there is little information published about the role of the clostridia in such infections.

This report presents here a case of malignant oedema associated with navel infection in a Merino lamb.

A 3 three-day-old Merino lamb was submitted to the Animal Health Unit of the National Institute of Agricultural Technology, Bariloche, Argentina. The lamb was from a flock of 50 ewes and 35 newborn lambs in the Trevelin area, Patagonia, Argentina. The animals were kept in a small paddock during the night and released to the field during the day. The ewes had been vaccinated for the first time in their lives with one dose only one dose of a clostridial vaccine containing toxoids of Clostridium septicum, Clostridium chauvoei and Clostridium perfringens types C and D, aapproximately 24 days before parturition.

A full necropsy was performed within 6 to 12 hours after death. Several smears were prepared from subcutaneous tissues from the navel. These were stained with Gram's stain and subjected to a direct fluorecent antibody test (FAT) for C. chauvoei, Clostridium sordellii, C. septicum and Clostridium novyi, as described by Sterne and & Batty (1975). The fluorescent antibodies were from Pragma (Kent, England). Tissues were collected from lung, heart and abdominal wall (including all layers) and fixed in 10% neutral buffered formalin, embedded in paraffin wax, sectioned at 4 µm, and stained with haematoxylin and eosin and Gram.

On post-mortem examination the animal was in good body condition. Severe diffuse haemorragic and gelatinous subcutaneous oedema was observed in the abdominal and thoracic regions, around and within the navel. One or two Gram positive bacillii per microscopic field were observed on the Gram-stained smears from subcutaneous tissues. These bacilli were pleomorphic and no spores were observed. Histopathology revealed mild vasculitis in the heart and severe, diffuse proteinaceous oedema in the umbilicus region with abundant basophilic and Gram positive baciliibacilli in the subcutaneous tissues. The FAT gave positive results to C. chauvoei and C. novyi on the tissue smears.

Malignant oedema has been described in many different animal species, including cattle, sheep and other ruminants. The condition is caused by the local proliferation and production of toxins by one or more of the following microorganisms: C. septicum, C. novyi, C. chauvoei, C. sordellii and C. perrfringens (Sterne & Batty, 1975). The disease occurs after the introduction of bacteria through skin wounds and the creation of anaerobic conditions in the area (Sterne & Batty, 1975). In this case, the distribution of the lesion around the navel suggests that the portal of entry was the wound caused by the rupture of the umbilicus after parturition, which admitted spores into the area.

Although navel infection of neonatal lambs by C. septicum has been reported before (Dennis, 1974) we are not aware of any published report of malignant oedema by C. chauvoei and/or C. novyi in newborn lambs.

It is apparent that newborn lambs are susceptible to malignant oedema. Prevention of this infection is based on passive immunity conferred by coolostral antibodies. To achieve this, boosting maternal antibody by double vaccination (or revaccination) about 4 weeks prior to parturition is recommended. This should give up to 12 weeks protection to the lambs (Lewis, 1999).

In the present case, C. novyi antigens were absent from the vaccine used and a sub-optimal vaccination protocol (i.e., the ewes had received only one dose of vaccine in their whole lives) was used. This is the most likely explanation for the lack of protective immunity demonstrated by the lamb.

Keywords:Lamb,malignant oedema, Clostridium chauvoei, Clostridium novyi




We thank Drs. W.R. Kelly and M. Sewell for critical review of this manuscripthis, Ms. E.N. Vidal, for excellent technical assistance, Dr. R. Assis for the translation to Portuguese and Ms. P. Lopez, S. Fitisemanu and P. Bolen for tyiping this manuscript. This work was carried out with support from Fondo Nacional para la Ciencia y la Tecnología (PICT 01-3591), Argentina.




Este relato descreve um caso de edema maligno associado com infecção do umbigo em um cordeiro merino de três dias de idade. Após necropsia, Clostridium chauvoei e Clostridium novyi foram detectados pela técnica de imunofluorescência direta (IFD) em impressões obtidas do tecido subcutâneo do umbigo.

Palavras-chave: Cordeiro, edema maligno, Clostridium chauvoei, Clostridium novyi




DENNIS, S.M. Perinatal lamb mortality in Western Australia. 4. Neonatal infections. Aust. Vet. J., v 50, p. 511-514, 1974.        [ Links ]

HAUGHEY, K.G. Perinatal lamb mortality – Its investigation, causes and control. Irish Vet. J., v 46, p.9-28, 1993.        [ Links ]

LEWIS, C.J. Clostridial diseases. In: MARTIN, W.B., AITKEN, I.D. (Eds.). Diseases of sheep. Oxford: Blackwell Science, 1999. p. 512.        [ Links ]

STERNE, M.; BATTY, I. Pathogenic Clostridia. London: Butterworthds, 1975. 168p.        [ Links ]

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