Worms in the Big Apple: Identifying Patterns of Toxocariasis Infection in New York City
For thousands of Americans, roundworm infection may pose a serious threat to their health. Toxocariasis, an illness caused by a parasitic roundworm, can potentially cause chronic health problems, including ocular infections, diminished lung function, and poor cognitive development. It is estimated to be one of the most prevalent neglected infections of poverty (NIP) in the United States, a group of “under the radar” infections that cause major problems for those living in poverty.
Public health officials know that toxocariasis is highly prevalent in urban areas and inner city neighborhoods, but beyond that, this disease isn’t tracked or treated like other illnesses where extensive background research is more accessible. The authors of a paper published in PLOS ONE in June of this year attempted to take a step closer to addressing this issue by looking at how data like ethnicity, education level, or neighborhood size in New York City can provide clues to the likelihood of toxocariasis occurrence.
The researchers in this study used the only source of population-based and location-specific information about toxocariasis that was available: a 1988-1994 National Health and Nutrition Examination Survey (NHANES) that contains a collection of data used to estimate the prevalence of this infection around the United States. By applying these statistics to highly detailed census data from urban areas of New York City, the authors could estimate the probability of toxocariasis in different demographics or neighborhoods. The results of this are shown in the map above.
As this second map indicates (click to enlarge), several different ethnicities in inner cities are at a higher risk for this infection. For instance, African Americans in New York City show a 64% greater risk of infection, and immigrants had a 92% greater chance of infection in comparison to those born in the US. Not only that, New Yorkers’ education levels also correlated with infection: the risk of toxocariasis was about 6% among US-born Latino women with a university education, and up to 57% among immigrant men with less than a high school education. These populations appear to be at particularly high risk for infection, and might be among the first groups surveyed in targeted sampling.
The results of this study are particularly telling for the US’ largest city, which holds almost 8.4 million people in all of its diverse neighborhoods. Wandering the streets of New York at any moment, you might hear one of 800 spoken languages. The dense populations of this city are key to understanding where and why these neglected infections of poverty can develop. More specifically, the colorful areas of these maps can be used to guide testing in inner city neighborhoods.
A few limitations of the study might be that the nationwide (NHANES) survey was conducted 15 years earlier, and it captured far fewer details than the New York City census data. Still, the vivid depictions of these statistics can provide us with much-needed maps for further research and potential surveillance. With more surveillance of this illness, we can gather more data, track, and study this disease. Once we have improved sampling methods, we can better address the public health needs of our urban areas.
Citation: Walsh MG, Haseeb MA (2014) Small-Area Estimation of the Probability of Toxocariasis in New York City Based on Sociodemographic Neighborhood Composition. PLoS ONE 9(6): e99303. doi:10.1371/journal.pone.0099303
Images: All images are from the article.