Prevalence of Borrelia burgdorferi-infected ticks from wildlife hosts, a response to Norris et al.

In a recent Letter to the Editor, Norris et al. questioned the validity of some of our data reported by Feria-Arroyo et al. The main issue investigated by us was the potential impact of climate change on the probable distribution of the tick vector Ixodes scapularis in the Texas-Mexico transboundary region. As an ancillary issue, an analysis of sequence data for the intergenic spacer of Borrelia burgdorferi was conducted. In the present letter, we provide further evidence supporting our original results, and advocate that extensive study of the population genetics of B. burgdorferi is needed in the Texas-Mexico transboundary region.

Implications of climate change on the distribution of the tick vector Ixodes scapularis and risk for Lyme disease in the Texas-Mexico transboundary region.

BACKGROUND: Disease risk maps are important tools that help ascertain the likelihood of exposure to specific infectious agents. Understanding how climate change may affect the suitability of habitats for ticks will improve the accuracy of risk maps of tick-borne pathogen transmission in humans and domestic animal populations. Lyme disease (LD) is the most prevalent arthropod borne disease in the US and Europe. The bacterium Borrelia burgdorferi causes LD and it is transmitted to humans and other mammalian hosts through the bite of infected Ixodes ticks. LD risk maps in the transboundary region between the U.S. and Mexico are lacking. Moreover, none of the published studies that evaluated the effect of climate change in the spatial and temporal distribution of I. scapularis have focused on this region. METHODS: The area of study included Texas and a portion of northeast Mexico. This area is referred herein as the Texas-Mexico transboundary region. Tick samples were obtained from various vertebrate hosts in the region under study. Ticks identified as I. scapularis were processed to obtain DNA and to determine if they were infected with B. burgdorferi using PCR. A maximum entropy approach (MAXENT) was used to forecast the present and future (2050) distribution of B. burgdorferi-infected I. scapularis in the Texas-Mexico transboundary region by correlating geographic data with climatic variables. RESULTS: Of the 1235 tick samples collected, 109 were identified as I. scapularis. Infection with B. burgdorferi was detected in 45% of the I. scapularis ticks collected. The model presented here indicates a wide distribution for I. scapularis, with higher probability of occurrence along the Gulf of Mexico coast. Results of the modeling approach applied predict that habitat suitable for the distribution of I. scapularis in the Texas-Mexico transboundary region will remain relatively stable until 2050. CONCLUSIONS: The Texas-Mexico transboundary region appears to be part of a continuum in the pathogenic landscape of LD. Forecasting based on climate trends provides a tool to adapt strategies in the near future to mitigate the impact of LD related to its distribution and risk for transmission to human populations in the Mexico-US transboundary region.

Monitoring unmet needs: using 2-1-1 during natural disasters.

BACKGROUND: Hurricanes Katrina and Rita struck the Gulf Coast forcing unprecedented mass evacuation and devastation. Texas 2-1-1 is a disaster communication hub between callers with unmet needs and community services at disaster sites and evacuation destinations. PURPOSE: To describe the location and timing of unmet disaster needs collected in real-time through Katrina-Rita disaster phases. METHODS: In 2008-2010, a total of 25 data sets of Texas 2-1-1 calls from August-December 2005 were recoded and merged. In 2011-2012, analysis was performed of unmet need types, with comparisons over time and location; mapping was adjusted by population size. RESULTS: Of 635,983 total 2-1-1 calls during the study period, 65% included primary disaster unmet needs: housing/shelter (28%); health/safety (18%); food/water (15%); transportation/fuel (4%). Caller demand spiked on Mondays, decreasing to a precipitous drop on weekends and holidays. Unmet needs surged during evacuation and immediate disaster response, remaining at higher threshold through recovery. Unmet need volume was concentrated in metropolitan areas. After adjusting for population size, "hot-spots" showed in smaller evacuation destinations and along evacuation routes. CONCLUSIONS: New disaster management strategies and policies are needed for evacuation destinations to support extended evacuation and temporary or permanent relocation. Planning and monitoring disaster resources for unmet needs over time and location could be targeted effectively using real-time 2-1-1 call patterns. Smaller evacuation communities were more vulnerable, exhausting their limited resources more quickly. Emergency managers should devise systems to more quickly authorize vouchers and reimbursements. As 2-1-1s expand and coordinate disaster roles nationwide, opportunities exist for analysis of unmet disaster needs to improve disaster management and enhance community resiliency.