Time-Space Clustering of Human Brucellosis, California, 1973–1992 1

Abstract

Infection with Brucella spp. continues to pose a human health risk in California despite great strides in eradicating the disease from domestic animals. Clustering of human cases in time and space has important public health implications for understanding risk factors and sources of infection. Temporal-spatial clustering of human brucellosis in California for the 20-year period 1973–1992 was evaluated by the Ederer-Myers-Mantel, Moran’s I, and population-adjusted Moran’s I procedures. Cases were clustered in concentrated agricultural regions in the first 5-year interval (1973–1977). Time-space clustering of human brucellosis cases in California late in the 20-year study period may reflect the distribution of Hispanic populations. Public health programs in California should focus on educating Hispanic populations about the risk of consuming dairy products, such as soft cheeses, made from unpasteurized milk.

From the discovery of the Malta fever?s agent to the discovery of a marine mammal reservoir, brucellosis has continuously been a re-emerging zoonosis

“…Human brucellosis is not considered a contagious disease [6,21,35]. Therefore, clustering could result from common-source outbreaks or time-space clustering of factors that increase the risk of infection [21,35].…”

“…Therefore, clustering could result from common-source outbreaks or time-space clustering of factors that increase the risk of infection [21,35]. In California, human brucellosis evolved between 1973 and 1992 from an occupational (slaughterhouse cases) to a foodborne illness with a higher incidence in Hispanics, especially in children and teenagers, compared with non-Hispanic whites and African Americans [21].…”

“…In California, human brucellosis evolved between 1973 and 1992 from an occupational (slaughterhouse cases) to a foodborne illness with a higher incidence in Hispanics, especially in children and teenagers, compared with non-Hispanic whites and African Americans [21]. Therefore, public health programs in California should focus on educating Hispanic populations about the risk of consuming dairy products, such as soft cheeses, made from unpasteurized milk [35]. The importance of screening household members of acute brucellosis cases in endemic areas, like Saudi Arabia, has recently been emphasized: screening family members of an index case of acute brucellosis detected additional cases [4].…”

Brucellosis Risk Factors in the Southwestern Province of Khuzestan, Iran

“…Rare cases of brucellosis suspected of sexual transmission have been reported (5). In most reported brucellosis outbreaks within families, the common food source has been the cause (15,16).…”

“…The actual prevalence rate of brucellosis at the province level is uncertain because of underreporting of data. Although risk factors for brucellosis, such as consumption of fresh cheese, undercooked meat and untreated animal milk, as well as skin contact with animals via slaughter and handling infected animal waste materials, are described in previous reports (11,12,(14)(15)(16), however, the risk factors in each area vary according to the socioeconomic and life-style of the population living in that particular region. Knowing the risk factors for brucellosis helps the local health policy makers and involved physicians in both preventive intervention and rapid epidemiological diagnosis to perform serological investigations and initiate proper treatment to prevent severe complications.…”