BUFFALOPOX
Authors: RAMANAN CHERUKOT , GHORPADE ASHOK , KALRA SATISH KALRA , MANN SUSHILA 
Published: May 2007

Case 1: A 22‐year‐old milker in a private dairy in Bhilai presented with painful skin lesions on both hands of 10 days duration. He also had a high‐grade fever for the last 5 days. There was a history of similar skin lesions on the hands of three other milkers working in the same dairy. Their skin lesions had subsided within 2 weeks after taking some treatment privately (nature of drugs not known). Eight out of 20 buffaloes in the dairy had multiple ulcerative lesions on the teats for the previous 3 weeks, reducing their milk yield to almost nil. Examination of the patient's skin revealed multiple bullous lesions on both the thenar eminences, fingers, and the right wrist joint. The lesions on the thenar eminence had a central erythematous zone, a whitish ring, and an eythematous halo at the periphery (Fig. 1). A few dark brown, dry, scabs were noted on the right forearm. The patient had a fever of 40°C (104°F) and bilateral axillary lymphadenitis with multiple firm, discrete, tender lymphnodes. Systemic examination and routine hematology tests were normal. Histopathologic examination of a bullous lesion revealed vacuolated cells in the stratum malpighii with multilocular vesicles. The rete ridges were elongated and a scant mononuclear infiltrate was found around dilated blood vessels in the upper dermis.

Case 2: A 20‐year‐old man working in the same dairy accompanied case 1. He had blackish lesions on both hands for 12 days. There was a history of blisters preceding the onset of the lesions but not of fever. Examination of the skin revealed blackish, well defined, nontender, drycrusted lesions on the palmar aspects of the fingers on both hands (Fig. 2). The patient was comfortable, afebrile, and had no lymphadenopathy or systemic abnormality. Routine hematologic investigations were normal.

Examination of the herd revealed extensive, erythematous, ulcerative, tender lesions with edema over the teats of eight buffaloes (Fig. 3). There were no other skin lesions.

Scabs collected from both the buffaloes (BPBB) and affected boys (BPBH) were grown in primary chicken embryo fibroblast cell (cef) culture, in which they produced cytopathic effects (cpe) followed by complete loss of cell sheet by 96 to 120 hours after infection. The period of appearance of CPE reduced to 48 hours after five passages in BPBB and nine passages in bpbh isolates.

The diagnosis was confirmed by inoculating the cell culture harvests in embryonated chicken eggs on chorioallantoic membrane (cam); the pock lesions produced were compared with buffalopox virus BP4 strain and vaccinia virus WR strain, adapted in cell cultures and inoculated in embryonated eggs. All four virus isolates produced characteristic pock lesions on CAM. Figure 4 depicts pock lesions produced by an BPBB isolate at passage level one, while Figure 5 shows pock lesions produced by BPBH at passage level three. Pock lesions in the initial passages were large, measuring 5 mm, whitish, raised slightly above the membrane, hemorrhagic in the center. In addition to these lesions, numerous small, circular, more discrete pock lesions were observed with increasing passage levels.