By Alexander J Schorr
Video Meeting Screenshot of Dr. Sayone Thihalolipavan
April 30, 2026 — In an interview with San Diego County Health Director Dr. Sayone Thihalolipavan originally aired on KNSJ Radio, he discussed the impacts of cuts by the federal government in research and testing of preventable diseases, vaccines, and emerging diseases in our region, including some exacerbated by climate change. Hear our full interview by clicking the audio link below, or scroll down to read highlights.
The CDC has slashed its support for local governments to test for 20 diseases including some forms of rabies, measles, monkeypox, chickenpox, Epstein-Barr syndrome, parasitic diseases and more. This comes about nationwide measles outbreak and locally, with recent cases of rapid bats and rat lungworm disease being found throughout local wildlife. Invasive Aedes Egyptian mosquitoes have become widespread across the region, resulting in a few cases of West Nile Virus, as well as a potential spreading of Zika Virus and Yellow Fever if they bite an infected traveler.
Dr. Thihalolipavan addressed the testing cuts. “The good news is that locally, we do have a pretty robust public health laboratory, and so for the most part, we are pretty self-sufficient. In terms of being able to do our own testing, of course, this is not ideal, because there is some kind of back-up testing and things like that that’s done at the federal level. We are probably in a better position than many other districts.”
Locally, Dr. Thihalolipavan has played a role in East County’s response to the Covid-19 pandemic, opioid overdoses, and hepatitis outbreaks, as well as continuing to help improve health care for the unhoused and the incarcerated. Dr. Thihalolipavan illustrates that due to a warming climate, pests in the forms of mosquitos, ticks, and rats are bringing with them transmittable and infectious diseases which can prove to be dangerous against the unvaccinated.
Invasive Mosquitos
As San Diego County warms and rainfall patterns shift, several tropical and subtropical diseases are expected to expand their reach into the region. The most immediate threats come from invasive mosquitoes that have already established a presence, though other fungal and parasitic risks are emerging as well.
West Nile Virus cases have occurred in San Diego in recent years. Chikungunya and Yellow Fever are also potential future threats as warmer temperatures reduce the virus incubation time within the mosquitoes, which will make the transmissions more efficient.
Additionally, Malaria— historically eradicated in the US— is coming back, as rising night temperatures and wetter habitats increase the risk of sporadic local outbreaks as suitable habitats move northward.
The Chagas Disease is transmitted by “kissing bugs,” which are parasites already present in California, but its transmission has been low because local bug species tend to defecate after leaving a host. As the climate warms, however, more aggressive tropical species may move north, and habitat fragmentation in areas like East County’s foothills is bringing humans into closer contact with these vectors.
There is also West Nile Virus (WNV), which is primarily spread by native Culex mosquitoes; invasive Aedes aegypti mosquitoes have become widespread across San Diego County. Though the Aedes aegypti can carry WNV, they are less effective at spreading it than native species. The “invasive pests,” often called “ankle-biters,” have different behaviors and risks than the native mosquitoes that carry WNV.
Also, in 2025, San Diego recorded its first case of locally acquired Dengue Fever, meaning that the person was infected by a local mosquito without traveling abroad. Climate models suggest southern coastal California will become increasingly suitable for seasonal transmission by mid-century. Additionally, while most cases of the Zika Virus are currently travel-related, local Aedes mosquitoes are capable of spreading the virus if they bite an infected person.
Native Culex mosquitos primarily feed on birds and then pass the virus to humans, and they are most active at dusk and dawn. Invasive Aedes, which consists of Aedes aegypti and Aedes albopictus, were first found in San Diego in 2014 and are now established throughout the county. They are mainly daytime biters and prefer humans over birds and can breed in as little as a bottle cap of water.
The County of San Diego Vector Control Program regularly monitors these pests and may conduct localized sprawling in neighborhoods with high activity. It is recommended to dump out all standing water around your home, as Aedes eggs can survive for months without water and can hatch as soon as they are submerged. Use EPA-registered repellents like DEET or Picaridin and ensure window screens are in good repair. If you are being bitten during the day or see neglected green swimming pools, you can report it to the San Diego Vector Control Program at (858) 694-2888.
When it comes to the spread of mosquitoes, Dr. Thihalolipavan stated that excessive heat holds a role in the festering of disease from mosquitoes: “it is really important that we continue to pay attention to what we could do to keep ourselves and our body temperatures cool, especially when there’s not as much cooling overnight. Then, your body’s working twice as hard and you don’t get enough time to recover during night time. That’s why we always recommend things like air conditioning or going to a cool zone.”
Dr. Thalolipavan advises the use of mosquito and bug repellent as well as the wearing of loose and long sleeved clothing when entering bug or vermin infested areas. For pet owners, it is wise to inspect and remove any ticks whenever possible. He emphasized the need to defend against disease carriers such as mosquitos by not leaving out standing water for them to fester and spread, and to have good screens on one’s household and keep the house sealed off as much as possible.
Tick-borne illnesses
Alpha-gal syndrome (AGS) is a serious and potentially life-threatening allergic condition that is triggered by a tick bite that causes an allergy to red meat and other products derived from mammals, including milk. Though it is mostly common in the Southeastern U.S., cases have been detected in many states and the ticks that can carry it have been found in California.
.In the US, AGS is most often linked to the Lone Star tick, which is not native to California. A 2025 study from UC Davis identified 76 lone star ticks across California, including sightings in the Bay Area and San Clemente. Cases in North America are often also associated with the Western blacklegged tick.
There is no cure for alpha-gel syndrome, but it can be managed through strict avoidance of mammal-centered products. A healthcare provider or allergist can perform a blood test for AGS-specific IgE antibodies. AGS symptoms are uniquely delayed, typically appearing 2 to 6 hours, which includes severe reactions like hives, nausea, stomach pain, and life-threatening anaphylaxis (swelling of the throat, difficulty breathing, or a sudden drop in blood pressure).
Climate modeling shows that coastal California provides prime environmental conditions for species of ticks, leading experts to warn that their presence is a potent future risk due to climate change and the movement of animals. To prevent tick bites while hiking in areas like Mission Trails or Torrey Pines, use EPA-registered repellents.
Tick-borne diseases including AGS as well as any others already found here, such as Lyme disease, which can be treated with oral antibiotics for a 10-21 day period (for adults and children over 8), with early treatment being more effective.
The fungal disease Valley Fever (Coccidioidomycosis), once limited to hot and dry areas, is expanding northward. In San Diego, researchers have linked dramatic increases in cases to shifting drought and rain patterns that disturb the soil and launch fungal spores into the air.
Cases of Flea-Borne Typhus are also rising in Los Angeles and Orange Counties. While not yet common in San Diego, the warming climate allows fleas in animals like rats and stray cats to remain active longer, increasing the potential for local spread.
Warmer coastal waters and frequent storm surges can increase the presence of Vibrio bacteria and E.coli. When it comes to the Tijuana River contamination, recent tropical storms have caused sewage overflows, leading to a 130% increase in local clinics treating respiratory issues and other illnesses related to toxic air and water exposure near the border.
Dr. Thihalolipavan emphasized that the spread of the latest and virulent tick-borne diseases, especially in East County, is unusual: “this not an area hot spot for tickborne diseases like versus [the] Rocky Mountains or other places like that.” He explained that “the best thing […] is prevention whenever possible. So, knowing that, wearing those kind of longer sleeves, longer pants, hats, and then of course, if we have kids or if when we come back from these events, just to look through your body, look through your hair or inspect. Dogs can get these too.”
New local threat: Rat Lungworm disease, a brain-eating parasitic illness transmitted through snails, slugs and rats
Most recently, Rat lungworm disease has created concern. Rat lungworm disease is a parasitic infection caused by the roundworm that typically affects the brain and spinal cord, often leading to a rare form of meningitis known as eosinophilic meningitis. While many cases resolve on their own, severe infections can cause permanent neurological damage and even death. There is no specific cure for rat lungworm; the parasite eventually dies on its own in the human body, though supportive care is often needed for pain and inflammation.
As of early 2026, no human cases of rat lungworm disease have been reported in San Diego County, however, researchers have confirmed that the parasite (Angiostrongylus cantonensis) is now established in local wildlife. While the risk to the general public is currently low, health officials and researchers from the San Diego Zoo Wildlife Alliance and the CDC recommend preventative care.
The disease was recently confirmed in opossums in seven locations countywide, as well as in rats and a koala at the San Diego Zoo. It can be transmitted through snails, slugs and rats. Residents are advised to carefully wash home-grown produce to avoid consuming slime from slugs or snails, and to control rodents on your property.
The best way to deal with rats is a combination of sanitation, exclusion, and trapping. Immediately remove food sources including trash and pet food; seal entry points with steel wool and snap taps.
CDC cuts in public health funding
San Diego County opened a state-of-the-art 52,000 square-foot Public Health Laboratory in 2025. Despite the new facility, the region faces a $40 million funding gap due to the CDC rescinding previously awarded grants for epidemiology and laboratory capacity.
The loss of federal support specifically threatens services that are used to respond to community outbreaks in areas like East County. This includes fewer frontline disease investigators to community outbreaks in areas like East county, and modernized tracking for vaccines and outbreaks which may revert to manual princesses.
The California Attorney General has joined a multi-state lawsuit to block these federal funding withdrawals, which local leaders describe as a direct hit to community safety.
Vaccines key to preventing many illnesses
For many diseases, from measles to COVID-19, Dr. Thihalolipavan illustrates that “the best thing […] is always prevention whenever possible,” and frames good holistic consistent medical advice with a healthcare provider, with vaccinations being a good form of defense.”
As of April 2026, federal vaccine recommendations are currently in a state of flux due to an unprecedented overhaul by the Department of Health and Human Services (DHHS) followed by a court-ordered stay that has temporarily paused many of these changes. The American Medical Association and the American Academy of Pediatricians strongly disagree with reduced vaccine recommendations by the Trump administration that the medical experts say could result in many deaths from preventable diseases, partiuclarly childhood diseases. A federal judge did also issue a preliminary injunction on March 16, 2026, which temporarily blocked the administration’s major revisions to the childhood vaccine schedule.
While the legal challenge moves through the courts, the federal vaccine recommendations have reverted to their pre-January 2026 state: this means that vaccines that were recently downgraded or restricted currently regain their status as standard, routine recommendations.
Federal health officials have stated that all vaccines recommended by the CDC as of December 31, 2025, will continue to be covered by ACA plans, Medicaid, and the Vaccines for Children (VFC) program without cost-sharing.
It is also important to note that states set school-entry vaccine requirements, not the federal government. For example, North Carolina officials confirmed their state requirements have not changed deposit the federal shifts.
As of 2026, the Trump administration has removed the requirement for states to report several immunization measures to the federal government as part of Medicaid and CHIP reporting. Pediatricians and major medical organizations, including the American Academy of Pediatrics (AAP), continue to advise following the original schedule to protect against severe illnesses.
Dr. Thihalolipavan stated that “We are fortunate in California that there was a trailer bill last year— AB144— that preserved access to immunizations and, you know, through your pharmacists, and the ability to follow these science-based recommendations which is what the American Academy of Pediatrics and others are also championing.”
He warned against the conflicting messaging between states and the federal government on behalf of families, where he advised that people continue to talk with a doctor or any “person that you have intimate healthcare conversations with.”
Effective Indoor Cleaners
Air quality and protection against the rising Tuberculosis cases— which have risen by about 17% since 2020— demand good air quality and a “cool down” of a household.
The California Air Resources Board (CARB) recommends choosing a CARB-certified air cleaner as they are legal for sale in California. Additionally, it is important to choose a mechanical air cleaner with a High Efficiency Particulate Air (HEPA) filter because it collects even very small particles well and does not emit ozone or other substances that can be harmful. These air cleaners can dramatically reduce indoor particle levels, in some cases by more than 90%.
Charcoal beds or filters in the air cleaner, especially those with certain coatings, can also help remove some gases produced by fires, which can be helpful in dealing with odors and for sensitive groups such as older individuals with pre-existening health conditions. If your air cleaner of choice includes an ionizer, UV bulb or other technology in addition to a HEPA filter, be sure it is one CARB’s certified air cleaner list. If one is on the list you will know that any ozone it emits is within safe limits.
Both particle and charcoal filters in air cleaners should be checked frequently and changed as needed. The owner’s manuals usually indicate the norma; replacement frequency; more frequent replacement may be needed during fire smoke conditions. The filters that APCD is handing out for TJRV includes both HEPA and activated carbon and potassium permanganate. Air Improvement Relief Effort Program – San Diego County Air District uses the Mod Jr from Oransi, though it does not endorse any specific brands and the guidance from CARB is most recommended.