A ProMED-mail post http://www.promedmail.org
ProMED-mail is a program of the International Society for Infectious Diseases http://www.isid.org
Date: Thu 3 Oct 2024
Source: KOST [edited] https://kost1035.iheart.com/featured/la-local-news/content/2024-10-03-5th-locally-acquired-dengue-case-confirmed-in-la-county/
Los Angeles County health officials Thursday [3 Oct 2024] continue to investigate a 5th locally acquired case of the mosquito-borne illness dengue, this time in a resident of El Monte. The latest patient does not appear to have any connection with the 4 previous reported infections, the county Department of Public Health said Wednesday [2 Oct 2024].
Health officials again stressed that locally acquired cases of dengue are extremely rare in areas where it has not been previously transmitted by mosquitoes. The county previously reported a cluster of 3 infections in the Baldwin Park area, and last week a 4th case was confirmed in a Panorama City resident. Health officials called the spate of local cases “unprecedented.”
None of the local patients had any history of travel to areas where dengue is endemic. In October and November of last year [2023], single locally acquired cases of dengue were confirmed by health officials in Pasadena and Long Beach.
Health officials noted that the symptoms of dengue often mirror those of other viruses, and they urged health-care providers to be “vigilant for dengue fever in patients with acute febrile illness and test for and report such cases of mosquito-borne diseases.”
— Communicated by: ProMED
FROM PROMED [It is interesting to note that the latest patient does not appear to have any connection with the 4 previous reported infections. There is a previously reported cluster of 3 cases in the Baldwin Park area, a single case in Panama City and now the latest one in El Monte. One wonders if there are several other dengue virus infected individuals in these 3 localities that have asymptomatic or very mild infections that have not resulted in medical attention so are not reported.
The above report does not indicate which vector mosquito was likely involved in dengue virus transmission in the 3 localities. As noted in the previously posted comment, the mosquitoes most likely involved are _Aedes aegypti_ or _Aedes albopictus_, both of which have been detected in California over the past 20 years. The preventive measures to avoid ongoing transmission are avoidance of mosquito bites and reduction of the mosquito populations. Mosquito control districts are undoubtedly attempting to control these vector mosquitoes, but that is a difficult task and requires collaboration with local residents to eliminate the water catchments in which these mosquitoes breed around their homes and other buildings.
Note that both _Aedes aegypti_ and _Aedes albopictus_ have been found in Los Angeles County. Which of these transmitted dengue virus to the residents is unknown. Locally acquired dengue virus infections remain extremely rare in California but occurrence of this cluster of cases indicates that local acquisition of dengue virus can occur. – Mod.TY
Note: The juxtaposition of these cases to the primary or imported cases has not been reported. As indicated above, it would seem that potentially other perhaps milder secondary cases have gone unnoticed, although these could still be a source of virus for mosquito infection making a vector control response difficult to focus geographically.