Prevalence, Risk Factors, and Phylogeny of Cytomegalovirus DNA in Breast Milk of Lactating Mothers

Cytomegalovirus (CMV) poses significant risks to infants and immunocompromised individuals. This study investigated the prevalence, associated risk factors, and phylogenetic profile of CMV DNA in the breast milk of lactating mothers in Khyber Pakhtunkhwa (KP), Pakistan. Breast milk samples (n = 406) were collected from mothers across four districts. Demographic factors were recorded, and CMV DNA was detected by conventional and nested PCR targeting the UL71 gene. Sanger sequencing was performed on the UL71 amplicons, and phylogenetic analysis was carried out using MEGA 7. CMV DNA was detected in 77/406 samples (18.97%), with higher prevalence among younger mothers, women from lower-income households, and those living in remote areas. Education level correlated positively with CMV awareness. UL71 sequences obtained from positive samples clustered closely with known Asian isolates; however, we failed to detect sequence variation within the UL71 region using Sanger sequencing. These findings do not exclude genetic diversity elsewhere in the CMV genome or the presence of minor variants. CMV is prevalent among lactating mothers in KP, particularly in socioeconomically disadvantaged groups. Rather than claiming broad genetic conservation, we report that no variation was detected in the sequenced UL71 region by Sanger sequencing; whole-genome or deep sequencing would be required to assess genome-wide diversity. These results underscore the need for continued surveillance and targeted public health interventions.