Decrease of measles cases in Mexico.

PIP: During November 27-December 5, 1995, in 21 states of Mexico, staff of PAHO's Special Program for Vaccines and Immunization and specialists from member countries interviewed personnel responsible for measles surveillance and reviewed thousands of daily patient records to evaluate Mexico's measles surveillance system. The personnel were well informed about case definitions and procedures. The team found only one case that fit the measles case definition. This case had not been reported to the surveillance system. Yet epidemiologists investigated 1206 suspected measles cases. The surveillance system could not identify chains of transmission for many of the suspected measles cases, suggesting that these cases were false positives or linked to undetected importations. The process for identifying and reporting cases of suspected measles was inefficient. Specifically, there were different case investigation forms for epidemiologists than for laboratories. The forms were long and requested too much clinical information, most of which was left blank. Patients often had to go through many medical consultation/examinations to make sure that they met the clinical case definition and to obtain a specimen for laboratory testing. There was no system at the local level for tracking suspected cases or once-investigated-now-discarded cases. The different levels of the health system had different databases. Ongoing training and feedback were rare. The Ministry of Health's (MOH) surveillance system did not communicate with that of other systems, e.g., Mexican Institute of Social Security. No ongoing evaluation or monitoring of the surveillance system took place. Based on the findings, the evaluation team made eight recommendations. The system should develop indicators for the quality of the surveillance system. Another identified need was integration of other institutions into MOH's surveillance system by standardizing surveillance training and sharing a common database of measles cases.^ieng