The epidemiology of nontuberculous mycobacterial lymphadenitis affecting New Zealand children 1986-95

To study the epidemiological trends of nontuberculous mycobacterial lymphadenitis affecting New Zealand children from 1986-95.

Cases were identified from the records of the three regional reference laboratories in New Zealand. All children of less than 16 years with a positive culture of nontuberculous mycobacteria from a lymph node tissue sample were included.

One hundred and sixty eight cases were identified, 43 in the first 5 years (no data available from Waikato) and 125 in the second 5 years of the study period. One hundred and fifty three (91%) of cases were in the 0-5 year age group and 101 (60%) were female. The head and neck was the most common site of infection accounting for 141 (84%) of all infection. In 161 (96%) of cases the causative organism was Mycobacterium avium intracellulare complex.

Nontuberculous mycobacterial infections cause a subacute lymphadenitis in preschool children, usually affecting the lymph nodes of the head and neck. The annual number of microbiologically confirmed cases in New Zealand had increased substantially over recent years, most notably since 1992. The reason for the increase is unknown but possible explanations include increased awareness of mycobacterial disease, external factors causing either changes in the distribution or virulence of mycobacteria in the environment and alterations in the human immune response.