Fig 1.
The Global Shipping Network containing Gulf State ports included 213 ports located in 69 countries.
Lines are logarithmically weighted to demonstrate connectivity between ports and indicate a highly connected shipping network. Inset map shows the U.S. Gulf of Mexico ports and is highlighted by the dotted-line box in the large map. Map created in the R package ‘maps’ [42] using basemap data from Natural Earth (www.naturalearthdata.com).
Table 1.
Ports along the Gulf Coast of the US with the highest relative likelihood of arrival (φj) by Ae. aegypti and Ae. albopictus via the international maritime trade network given a constant transmission potential (λ) of 0.5.
The total number of arrivals of fully cellular container ships at each port was strongly correlated with relative likelihood of arrival by both Ae. aegypti (r2 = 0.999, P > 0.0001) and Ae. albopictus (r2 = 0.999, P > 0.0001) during this time frame. This was reflective of the high connectivity between ports, which implies high risk for movement of Aedes spp. mosquitoes between these cities. While Houston seems to play a role as a hub for international arrivals, New Orleans and Mobile receive a great number of shipments from domestic ports, including Houston. Count data represents arrivals by fully cellular container ships from January 1st to December 31st, 2012.
Fig 2.
Effectiveness mosquito detection and removal programs displayed as the proportion of populations that were established from containers that initially contained viable mosquito populations.
A) As the effectiveness of mosquito detection and removal increased, the proportion of mosquito populations decreased even when the probability of a container being move to shore was as low as 20%. B) The number of stops at ports on a shipping route generally did not interact with the probability of mosquito population detection and removal to influence mosquito population establishment rate. However, when detection rates were low and there were relatively few stops, the number of stops was positively related to the proportion of mosquito populations established.
Table 2.
Ports with the highest immediate connectivity to our seven target ports in the US Gulf States.
Since nearly all maritime arrivals in the Gulf passed most recently through ports on the Atlantic seaboard, in the Caribbean, or in other ports on the Gulf of Mexico, all of which host populations of both Ae. aegypti and Ae. albopictus, mosquito populations from these ports must reasonably be assumed to be the most likely to arrive in target ports. Data represents arrivals by fully cellular container ships from January 1st to December 31st, 2012.