Veterinary field test as screening tool for mastitis and HIV-1 viral load in breast milk from HIV-infected Zambian women

Authors: DOROSKI, STEPHANIE - TUFTS UNIVERSITY; THEA, DONALD - BOSTON UNIVERSITY; SAPERSTEIN, GEORGE - TUFTS UNIV-SCHOOL VET MED; RUSSELL, ROBERT - TUFTS UNIV - HNRC; Paape, Max; HINCKLEY, LYNN - UNIV OF CONNECTICUT; DECKER, WILLIAM - CHILDRENS HOSPITAL IN LA; GHOSH, MRINAL - CHILDRENS HOSPITAL IN LA; SEMRAU, KATHERINE - UNIVERSITY OF ZAMBIA; SINKALA, MOSES - LUSAKA HEALTH MGMT TEAM; KASONDE, PRISCA - UNIVERSITY OF ZAMBIA; KANKASA, CHIPEPO - UNIVERSITY OF ZAMBIA; ALDROVANDI, GRACE - CHILDRENS HOSPITAL IN LA; HAMMER, DAVIDSON - TUFTS UNIVERSITY

Submitted to: Breastfeeding Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2007
Publication Date: 9/1/2007
Citation: Doroski, S.M., Thea, D.M., Saperstein, G., Russell, R., Paape, M.J., Hinckley, L., Decker, W.D., Ghosh, M.K., Semrau, K., Sinkala, M., Kasonde, P., Kankasa, C., Aldrovandi, G.M., Hammer, D.H. 2007. Veterinary field test as screening tool for mastitis and HIV-1 viral load in breast milk from HIV-infected Zambian women. Breastfeeding Medicine.2(3):172-175.

Interpretive Summary: The Pyronin-Y methyl green stain, developed by scientists at the USDA, Beltsville, for identification of cells in goat milk, was recently used in Zambia, Africa to determine if breastfeeding would increase the risk of transmission of HIV in breast milk from mothers with mastitis, an inflammation of the mammary gland caused by bacterial infection. Mastitis causes a breakdown in the blood milk barrier and results in the influx of blood components like white blood cells and sodium into milk. Goat milk is similar to human milk because in addition to cells there is a high concentration of cytoplasmic particles, that are similar to cells but contain no nucleus. So, in order to distinguish cells from cytoplasmic particles, a stain specific for nuclear DNA was required. The results from that study indicated that cell counts in milk, concentration of sodium in milk and electrical conductivity of milk (an indirect measure of sodium) were correlated to increased HIV viral load. Use of the Pyronin-Y methyl green stain for determination of cell count in milk or electrical conductivity could prove useful in reducing the risk of HIV through breast feeding.

Technical Abstract: Both clinical and subclinical mastitis are believed to increase the risk of mother-to-child transmission (MTCT) of HIV-1 through breastfeeding, perhaps due to increased viral load. We hypothesized that a veterinary screening test for mastitis, the California Mastitis (CMT), would be a reliable indicator of high cell counts in human milk, and that cell count, using the USDA Pyronin-Y methyl green stain, would correlate with other measures of mammary permeability. The relationship between breast milk indicators of mastitis and breast milk quantity HIV-1 was also examined, in hopes that the CMT could be used as an indirect screening tool for high viral load in milk. The validity of the CMT was tested on 237 cross-sectional milk samples from HIV-infected Zambian women. Electrical conductivity was measured in 85 of these samples. Sodium concentrations and HIV-1 RNA were measured in all 4-month postpartum samples (n=53). Mean total cell counts in each CMT scoring category significantly differed from one another (P< 0.01). In addition, cell counts positively correlated with sodium concentrations r = .389, P = .006) and electrical conductivity (r = .649, P < .001). Sodium concentration correlated with viral load (r = .291, P = .05), while electrical conductivity tended to correlate with HIV-1 RNA (r = .331, P = .107). No correlation was found between milk viral load and cell count. While the CMT is a valid screening tool for high cell counts in human milk, we do not recommend it as a method to indirectly assess breast milk HIV viral load.