The analysis and recognition of disease clustering in space and its representation on a map is an important problem in epidemiology. An approach using mixture models to identify spatial heterogeneity in disease risk and map construction within an empirical Bayes framework is described. Once heterogeneity is detected, the question arises as how explanatory variables could be included in the model. A mixed Poisson regression approach to include covariates is presented. The methods are illustrated using data for tuberculosis from Berlin in 1991.

Algorithms↗

PubMedDate not supplied

Space-time mixture modelling of public health data.

This paper aims to enlarge the usual scope of disease mapping by means of dynamic mixtures (DMDM) in case a time component is involved in the data. A special mixture model is suggested which looks for space-time components (clusters) simultaneously. The idea is illustrated using data on female lung cancer from the East German cancer registry for 1960-1989. The conventional mixed Poisson regression model is used as a third model for comparison. The models are discussed in terms of their benefits, difficulties and ease in interpretation, as well as their statistical meaning. Some ideas on evaluation of these models are also included.

Algorithms↗

PubMedDate not supplied

Co-infection by Cryptococcus neoformans and Mycobacterium avium intracellulare in AIDS.

In the observation of various opportunistic pathogens in HIV-positive persons, co-infection by Cryptococcus neoformans together with Mycobacterium avium intracellulare was found if there was a CD4 lymphocyte count as low as 3-20 microl. In 1540 HIV-positive patients under treatment at a Berlin hospital (Auguste-Viktoria-Krankenhaus) during 1985-1994, all AIDS-relevant diseases were examined in a multivariate analysis as variables of influence on the manifestation of a systemic Mycobacterium avium complex (MAC) infection. The analysis involved data on 36 cases of cryptococcosis and 202 cases with a typical clinical course in whom MAC had been detected at sterile body sites. As significant and independent factors of influence, the following were identified: C. neoformans infection, wasting syndrome, lower age, low CD4 lymphocyte count and preceding Pneumocystis carinii pneumonia (PcP) prophylaxis. Cryptococcosis ranged first with an odds ratio of 2.75. The concomitant manifestation of cryptococcosis and systemic MAC infection in six patients is shown. Because both opportunists, C. neoformans and avian mycobacteria, may have their common habitat in droppings of defined species of pet birds, a common source of infection deserves further clinical and epidemiological attention.

Journal Article↗

PubMedDate not supplied

Co-infection by Cryptococcus neoformans and Mycobacterium avium intracellulare in AIDS. Clinical and epidemiological aspects.

In the observation of various opportunistic pathogens in HIV-positive persons, co-infection by Cryptococcus neoformans together with Mycobacterium avium intracellulare was found if there was a CD4 lymphocyte count as low as 3-20/microliters. In 1540 HIV-positive patients under treatment at a Berlin hospital (Auguste-Viktoria-Krankenhaus) during 1985-1994, all AIDS-relevant diseases were examined in a multivariate analysis as variables of influence on the manifestation of a systemic Mycobacterium avium complex (MAC) infection. The analysis involved data on 36 cases of cryptococcosis and 202 cases with a typical clinical course in whom MAC had been detected at sterile body sites. As significant and independent factors of influence, the following were identified: C. neoformans infection, wasting syndrome, lower age, low CD4 lymphocyte count and preceding Pneumocystis carinii pneumonia (PcP) prophylaxis. Cryptococcosis ranged first with an ods ratio of 2.75. The concomitant manifestation of cryptococcosis and systemic MAC infection in six patients is shown. Because both opportunists, C. neoformans and avian mycobacteria, may have their common habitat in droppings of defined species of pet birds, a common source of infection deserves further clinical and epidemiological attention.

AIDS-Related Opportunistic Infections↗