Vector-borne diseases (VBD) are viruses and bacteria spread by vectors including mosquitoes, ticks and fleas, and they can cause a variety of illnesses in humans. The vectors ingest the microorganisms from an infected host and transmit to a new host through a bite. Many public health laboratories test for VBDs that are endemic (see list below) as well as those emerging or re-emerging in the US.
APHL works with CDC and public health laboratories to promote best practices, develop guidance and hold important laboratory trainings related to the most commonly found vector-borne diseases in the country. Public health laboratories are integral to performing high quality testing to assess regional disease burden and inform the nation's response to vector-borne diseases.
Active Responses
Dengue Virus
APHL continues to monitor the unprecedented number of
dengue cases in 2024–2025 (CDC Situation Summary) and is coordinating with federal partners and public health laboratories to ensure appropriate and sufficient laboratory testing to identify DENV.
Public health laboratories are likely to see an increase in requests for testing of persons with travel history to places where
dengue is common and could lead to more local transmission in the US. Additionally, based on CDC models, many mid- to southern states in the US are home to competent vectors for dengue virus, so travel associated cases could also cause limited local transmission within the
Aedes mosquitoes range.
Testing and Surveillance:
There are five FDA-cleared (or EUA authorized) tests available; two nucleic acid amplification tests (NAAT) from CDC
Trioplex Real-Time RT-PCR Assay (EUA) and
CDC DENV 1-4 rRT-PCR Multiplex Assay (510K), two serologic assays from InBios International-IgM ELISA and NS1 ELISA and the BioFire global fever panel. The CDC NAAT methods are currently available to public health laboratories (DenguePCROrdering@cdc.gov) while the other assays are commercially available. Commercial Laboratories also offer testing for DENV.
Resources:
Oropouche Virus
Oropouche virus (OROV), initially identified over 70 years ago is endemic to the Amazon basin and certain Central and South American countries. Transmitted by biting midges which are small flies, often called "no-see-ums," the virus was identified as causing large outbreaks in 2023 and continued unprecedented levels of transmission across the Caribbean as well as South and Central America. Identification of possible cases of vertical transmission between mother and fetus are being investigated.
Preliminary diagnosis is based on the patient's clinical symptoms, location where infection likely occurred and activities leading to risk of exposure. Clinical and surveillance testing is currently limited and should be coordinated through state and local public health laboratories/departments.
For patients meeting the suspect case definition, CDC can perform CLIA-validated testing using RT-PCR to detect OROV RNA and/or PRNT to detect neutralizing OROV antibody on serum and/or CSF. Further information on CDC testing, reporting and management of cases can be found in the interim CDC documents below. In addition, the Florida Bureau of Laboratories has an RT-PCR assay available and New York State Department of Health-Wadsworth Center has an RT-PCR and PRNT assay available. Commercially available testing for OROV RNA can be obtained at
Nexus Medical Laboratories.
Interim CDC Guidance Documents:
Resources and Additional Information:
Endemic Vector-borne Diseases
There are several endemic VBDs of public health concern within the US. The distribution of these are not equally distributed and therefore testing at any given public health laboratory will vary. The most commonly recognized include the following:
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Borrelia burgdorferi (Lyme Disease)
- Colorado Tick Fever Virus (CTFV)
- Eastern Equine Encephalitis Virus (EEEV)
- Jamestown Canyon Virus (JCV)
- LaCrosse Encephalitis Virus (LCV)
- Powassan Virus
- St. Louis Encephalitis Virus (SLEV)
- West Nile Virus (WNV)
APHL Resources
Invasive Vector-borne Diseases
Beyond the two active responses mentioned above there are other vector-borne diseases globally; those most likely to be seen in the US include zika and chikungunya viruses. In the US these viruses are predominantly seen in travelers returning to the US, some local transmission can and has occurred. Many public health laboratories maintain capability to test for one or more of these and other invasive VBDs.
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Chikungunya virus: For chikungunya virus protocols visit APHL's Emerging Infectious Disease Protocols (member access only).
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Dengue virus: State and local public health laboratories diagnose suspected dengue cases through molecular methods and serology including PRNT.
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Orpouche virus: Some state and local public health laboratories have brought molecular testing or PRNT to detect suspected oropouche cases in-house.
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Zika: Following the
Zika virus response, APHL published a
book highlighting the experiences of public health laboratories keeping up with the Zika outbreak and the challenges they faced during the response.
Vector-borne Diseases Training and Educational Resources
APHL, in collaboration with CDC, has developed training and educational resources to promote competency, quality and safety in vector-borne disease testing practices. These resources are primarily designed for laboratorians interested in learning more about the several testing methods available for testing for vector-borne diseases. Most of these trainings are available in APHL's Learning Center.
Access the APHL Learning Center
Recorded Webinars and Trainings