Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Great Border Mosquito Massacre (or Dengue and Dengue Hemorrhagic Fever at the TX-MX Border) Mary Hayden Research Review October 4, 2007.

Similar presentations


Presentation on theme: "The Great Border Mosquito Massacre (or Dengue and Dengue Hemorrhagic Fever at the TX-MX Border) Mary Hayden Research Review October 4, 2007."— Presentation transcript:

1 The Great Border Mosquito Massacre (or Dengue and Dengue Hemorrhagic Fever at the TX-MX Border) Mary Hayden Research Review October 4, 2007

2 Presentation Outline Recent History of Dengue in Mexico/South Texas 2005 Outbreak Investigation Methods Results Current Study

3 Dengue Fever (DF) and Dengue Hemorrhagic Fever (DHF) Flavivirus transmitted by Aedes mosquitoes Disease characterized by sudden onset of headache + fever – myalgia – anorexia - arthralgia Endemic in tropics Increasing incidence worldwide Estimated million dengue infections annually

4 Aedes aegypti and Dengue Fever Aedes aegypti is the principal vector of yellow fever and the dengue viruses. Peri-domestic, day-biting mosquito which breeds in and around humans Prefers to breed in artificial containers such as vases, pet dishes, 55 gallon drums

5 Study Region - Matamoros, MX and Brownsville, TX Matamoros

6 Dengue in South Texas 4 outbreaks with local transmission Year# CasesSerotype , Hafkin B. Am J Trop Med Hyg 1982; 31(6), Gubler D. "Dengue and Dengue Hemorrhagic Fever." Tropical Infectious Diseases. 2nd ed. MMWR 1996;45(39);841-4 MMWR 2000; 50:57-9

7 YearNo. dengue cases No. DHF casesTotal no. of dengue cases Percent DHF Source: Boletín Epidemiolgía [Spanish]. México, D.F. Dirección General de Epidemiología, 2001 – Available at Cases of Dengue Fever and Dengue Hemorrhagic Fever (DHF) Reported in Tamaulipas, Mexico from 2000 to 2006

8 Number of cases 8 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Matamoros Cameron County Cases of dengue by week of report, Matamoros (Mexico) and Cameron County, TX, 2005 Serosurveys, 5-15 Dec Autochthnous DHF, Cameron County

9 Methods Two stage cluster sample design (WHO) - systematically selected census tracts after ordering by socioeconomic status (SES) and then randomly selected households from within the sampled census tract Household-level –Questionnaire with travel history –Blood samples –Entomological survey Serology testing Results were weighted to reflect each individual’s chance of selection in the sample.

10 Seroprevalence of anti-dengue IgM and IgG Antibodies* by City MatamorosBrownsville Households participating 111 (78% of total visited) 118 (73% of total visited) Serum Samplesn = 132n = 141 Immunoglobulin M (IgM) positive 22.8% (13.3 to 32.3) * n = % (0 to 5.4) * n = 4 Immunoglobulin G (IgG) positive 76.6% (64.7—88.5) * n = % (26.7—49.8) * n = 47 * Weighted point estimate and (95% confidence interval).

11 Spatial Distribution of IgM Positive Participants Brownsville Matamoros IgM Positive IgM Negative Source: Rafael Moreno, U. Colorado

12 Select Housing Characteristics * of Participants by City Characteristic Matamoros Brownsville Central A/C 4% 46% Room A/C 27% 40% Intact screens65% 61% Mean no. occupants/home Mean distance to neighbors (m) Mean lot size (m 2 ) * Weighted point estimates

13 MatamorosBrownsville Ae. aegypti or Ae. albopictus Ae. aegypti or Ae. albopictus Breteau index (containers/100 houses) House index % houses infested Container index %with water infested Mosquito Larval Indices* by City * Weighted data

14

15 Human-Environmental Interaction and the Effect of Waste Tire Removal on Risk for Dengue Fever Infection in Brownsville, TX and Matamoros, MX. Funded by: Pan American Health Organization EPA

16

17 Brownsville, TX and Matamoros, MX Assess human health-environmental factors, specifically the effect of waste tire proximity on human-vector contact through measurement of mosquito indices Evaluate Ae. aegypti and Ae. albopictus resistance to a widely utilized organophosphate – temephos Qualitatively evaluate household level perception of risk of dengue transmission from waste tires and options for control

18 Rio Bravo

19

20

21

22

23

24 Toxorhynchites

25

26 Tire Interventions Piles A+BPiles C+DPiles E+F BrownsvilleToxorhynchitesToxorhynchites + Mesocyclops longesitus No treatment MatamorosAltosid (chemical intervention) Mesocyclops longesitus No treatment Evaluation of intervention will take place the end of October


Download ppt "The Great Border Mosquito Massacre (or Dengue and Dengue Hemorrhagic Fever at the TX-MX Border) Mary Hayden Research Review October 4, 2007."

Similar presentations


Ads by Google