No specific therapy is available at present for La Crosse encephalitis, and management is limited to alleviating the symptoms and balancing fluids and electrolyte levels. Intravenous ribavirin is effective against La Crosse encephalitis virus in the laboratory, and several studies in patients with severe, brain biopsy confirmed, La Crosse encephalitis are ongoing.

In a trial with 15 children being infected with La Crosse viral encephalitis were treated at certain phases with ribavirin (RBV). RBV appeared to be safe at moderate doses. At escalated doses of RBV, adverse events occurred and then the trial was discontinued. Nonetheless, this was the largest study of antiviral treatment for La Crosse encephalitis.

Most people recover from West Nile virus without treatment. No specific treatment is available for WNV infection. In mild cases over the counter pain relievers can help ease mild headaches and muscle aches in adults. In severe cases treatment consists of supportive care that often involves hospitalization, intravenous fluids, pain medication, respiratory support, and prevention of secondary infections.

There is currently no effective marburgvirus-specific therapy for MVD. Treatment is primarily supportive in nature and includes minimizing invasive procedures, balancing fluids and electrolytes to counter dehydration, administration of anticoagulants early in infection to prevent or control disseminated intravascular coagulation, administration of procoagulants late in infection to control hemorrhaging, maintaining oxygen levels, pain management, and administration of antibiotics or antimycotics to treat secondary infections. Experimentally, recombinant vesicular stomatitis Indiana virus (VSIV) expressing the glycoprotein of MARV has been used successfully in nonhuman primate models as post-exposure prophylaxis. Novel, very promising, experimental therapeutic regimens rely on antisense technology: phosphorodiamidate morpholino oligomers (PMOs) targeting the MARV genome could prevent disease in nonhuman primates. Leading medications from Sarepta and Tekmira both have been successfully used in European humans as well as primates.

Prophylaxis by vaccination, as well as preventive measures like protective clothing, tick control, and mosquito control are advised. The vaccine for KFDV consists of formalin-inactivated KFDV. The vaccine has a 62.4% effectiveness rate for individuals who receive two doses. For individuals who receive an additional dose, the effectiveness increases to 82.9%. Specific treatments are not available.

There is no cure for EEE. Treatment consists of corticosteroids, anticonvulsants, and supportive measures (treating symptoms) such as intravenous fluids, tracheal intubation, and antipyretics. About four percent of humans known to be infected develop symptoms, with a total of about six cases per year in the US. A third of these cases die, and many survivors suffer permanent brain damage.

The disease is incurable once manifested, so there is no specific drug therapy for TBE. Symptomatic brain damage requires hospitalization and supportive care based on syndrome severity. Anti-inflammatory drugs, such as corticosteroids, may be considered under specific circumstances for symptomatic relief. Tracheal intubation and respiratory support may be necessary.

Prevention includes non-specific (tick-bite prevention, tick checks) and specific prophylaxis in the form of a vaccine. TBE immunoglobulin is no longer used. Tick-borne encephalitis vaccine is very effective and available in many disease endemic areas and in travel clinics.

Treatment is symptomatic and supportive. Children with hydrocephalus often need a ventriculoperitoneal shunt. Nucleoside analog ribavirin is used in some cases due to the inhibitory effect the agent has "in vitro" on arenaviruses. However, there is not sufficient evidence for efficacy in humans to support routine use. The only survivor of a transplant-associated LCMV infection was treated with ribavirin and simultaneous tapering of the immunosuppressive medications. Early and intravenous ribavirin treatment is required for maximal efficacy, and it can produce considerable side effects. Ribavirin has not been evaluated yet in controlled clinical trials.

Use of ribavirin during pregnancy is generally not recommended, as some studies indicate the possibility of teratogenic effects. If aseptic meningitis, encephalitis, or meningoencephalitis develops in consequence to LCMV, hospitalization and supportive treatment may be required. In some circumstances, anti-inflammatory drugs may also be considered. In general, mortality is less than one percent.

Development of new therapies has been hindered by the lack of appropriate animal model systems for some important viruses and also because of the difficulty in conducting human clinical trials for diseases that are rare. Nonetheless, numerous innovative approaches to antiviral therapy are available including candidate thiazolide and purazinecarboxamide derivatives with potential broad-spectrum antiviral efficacy. New herpes virus drugs include viral helicase-primase and terminase inhibitors. A promising new area of research involves therapies based on enhanced understanding of host antiviral immune responses.

There is no specific treatment for the canine distemper. As with measles, the treatment is symptomatic and supportive. The supportive care is geared towards treating fluid/electrolyte imbalances, neurological symptoms, and preventing any secondary bacterial infections. Examples include administering fluids, electrolyte solutions, analgesics, anticonvulsants, broad spectrum antibiotics, antipyretics, parenteral nutrition and nursing care.

There is no specific treatment for Japanese encephalitis and treatment is supportive, with assistance given for feeding, breathing or seizure control as required. Raised intracranial pressure may be managed with mannitol. There is no transmission from person to person and therefore patients do not need to be isolated.

A breakthrough in the field of Japanese encephalitis therapeutics is the identification of macrophage receptor involvement in the disease severity. A recent report of an Indian group demonstrates the involvement of monocyte and macrophage receptor CLEC5A in severe inflammatory response in Japanese Encephalitis infection of the brain. This transcriptomic study provides a hypothesis of neuroinflammation and a new lead in development of appropriate therapeutic against Japanese encephalitis.

The disease can be prevented in horses with the use of vaccinations. These vaccinations are usually given together with vaccinations for other diseases, most commonly WEE, VEE, and tetanus. Most vaccinations for EEE consist of the killed virus. For humans there is no vaccine for EEE so prevention involves reducing the risk of exposure. Using repellent, wearing protective clothing, and reducing the amount of standing water is the best means for prevention

Treatments of proven efficacy are currently limited mostly to herpes viruses and human immunodeficiency virus. The herpes virus is of two types: herpes type 1 (HSV-1, or oral herpes) and herpes type 2 (HSV-2, or genital herpes). Although there is no particular cure; there are treatments that can relieve the symptoms. Drugs like Famvir, Zovirax, and Valtrex are among the drugs used, but these medications can only decrease pain and shorten the healing time. They can also decrease the total number of outbreaks in the surrounding. Warm baths also may relive the pain of genital herpes.

Human Immunodeficiency Virus Infection (HIV) is treated by using a combination of medications to fight against the HIV infection in the body. This is called antiretroviral therapy (ART). ART is not a cure, but it can control the virus so that a person can live a longer, healthier life and reduce the risk of transmitting HIV to others around him. ART involves taking a combination of HIV medicines (called an HIV regimen) every day, exactly as prescribed by the doctor. These HIV medicines prevent HIV Virus from multiplying (making copies of itself in the body), which reduces the amount of HIV in the body. Having less HIV in the body gives the immune system a chance to recover and fight off infections and cancers. Even though there is still some HIV in the body, the immune system is strong enough to fight off infections and cancers. By reducing the amount of HIV in the body, HIV medicines also reduce the risk of transmitting the virus to others. ART is recommended for all people with HIV, regardless of how long they’ve had the virus or how healthy they are. If left untreated, HIV will attack the immune system and eventually progress to AIDS.

People reduce the chance of getting infected with LACV by preventing mosquito bites. There is no vaccine or preventive drug.

Prevention measures against LACV include reducing exposure to mosquito bites. Use repellent such as DEET and picaridin, while spending time outside, especially at during the daytime - from dawn until dusk. "Aedes triseriatus" mosquitoes that transmit (LACV) are most active during the day. Wear long sleeves, pants and socks while outdoors. Ensure all screens are in good condition to prevent mosquitoes from entering your home. "Aedes triseriatus" prefer treeholes to lay eggs in. Also, remove stagnant water such as old tires, birdbaths, flower pots, and barrels.

Infection with Japanese encephalitis confers lifelong immunity. There are currently three vaccines available: SA14-14-2, IC51 (marketed in Australia and New Zealand as JESPECT and elsewhere as IXIARO) and ChimeriVax-JE (marketed as IMOJEV). All current vaccines are based on the genotype III virus.

A formalin-inactivated mouse-brain derived vaccine was first produced in Japan in the 1930s and was validated for use in Taiwan in the 1960s and in Thailand in the 1980s. The widespread use of vaccine and urbanization has led to control of the disease in Japan, Korea, Taiwan, and Singapore. The high cost of this vaccine, which is grown in live mice, means that poorer countries have not been able to afford to give it as part of a routine immunization program.

The most common adverse effects are redness and pain at the injection site. Uncommonly, an urticarial reaction can develop about four days after injection. Vaccines produced from mouse brain have a risk of autoimmune neurological complications of around 1 per million vaccinations. However where the vaccine is not produced in mouse brains but in vitro using cell culture there is little adverse effects compared to placebo, the main side effects are headache and myalgia.

The neutralizing antibody persists in the circulation for at least two to three years, and perhaps longer. The total duration of protection is unknown, but because there is no firm evidence for protection beyond three years, boosters are recommended every three years for people who remain at risk. Furthermore, there is also no data available regarding the interchangeability of other JE vaccines and IXIARO.

In September 2012 the Indian firm Biological E. Limited has launched an inactivated cell culture derived vaccine based on SA 14-14-2 strain which was developed in a technology transfer agreement with Intercell and is a thiomersal-free vaccine.

Oropouche Fever has no cure or specific therapy so treatment is done by relieving the pain of the symptoms through symptomatic treatment. Certain oral analgesic and anti-inflammatory agents can help treat headaches and body pains. In extreme cases of oropouche fever the drug, Ribavirin is recommended to help against the virus. This is called antiviral therapy. Treatments also consist of drinking lots of fluids to prevent dehydration.

Asprin is not a recommended choice of drug because it can reduce blood clotting and may aggravate the hemorrhagic effects and prolong recovery time.

The infection is usually self-limiting and complications are rare. This illness usually lasts for about a week but in extreme cases can be prolonged. Patients usually recover fully with no long term ill effects. There have been no recorded fatalities resulting from oropouche fever.

Medical management of VHF patients may require intensive supportive care. Antiviral therapy with intravenous ribavirin may be useful in Bunyaviridae and Arenaviridae infections (specifically Lassa fever, RVF, CCHF, and HFRS due to Old World Hantavirus infection) and can be used only under an experimental protocol as investigational new drug (IND) approved by the U.S. Food and Drug Administration (FDA). Interferon may be effective in Argentine or Bolivian hemorrhagic fevers (also available only as IND).

In unvaccinated humans, rabies is almost always fatal after neurological symptoms have developed.

Vaccination after exposure, PEP, is highly successful in preventing the disease if administered promptly, in general within 6 days of infection. Begun with little or no delay, PEP is 100% effective against rabies. In the case of significant delay in administering PEP, the treatment still has a chance of success.

Five of the first 43 patients (12%) treated with the Milwaukee protocol survived, and those receiving treatment survived longer than those not receiving the treatment.

With the exception of yellow fever vaccine neither vaccines nor experimental vaccines are readily available. Prophylactic (preventive) ribavirin may be effective for some bunyavirus and arenavirus infections (again, available only as IND).

VHF isolation guidelines dictate that all VHF patients (with the exception of dengue patients) should be cared for using strict contact precautions, including hand hygiene, double gloves, gowns, shoe and leg coverings, and faceshield or goggles. Lassa, CCHF, Ebola, and Marburg viruses may be particularly prone to nosocomial (hospital-based) spread. Airborne precautions should be utilized including, at a minimum, a fit-tested, HEPA filter-equipped respirator (such as an N-95 mask), a battery-powered, air-purifying respirator, or a positive pressure supplied air respirator to be worn by personnel coming within 1,8 meter (six feet) of a VHF patient. Multiple patients should be cohorted (sequestered) to a separate building or a ward with an isolated air-handling system. Environmental decontamination is typically accomplished with hypochlorite (e.g. bleach) or phenolic disinfectants.

Treatment after exposure can prevent the disease if administered promptly, generally within 10 days of infection. Thoroughly washing the wound as soon as possible with soap and water for approximately five minutes is effective in reducing the number of viral particles. Povidone-iodine or alcohol is then recommended to reduce the virus further.

In the US, the Centers for Disease Control and Prevention recommends people receive one dose of human rabies immunoglobulin (HRIG) and four doses of rabies vaccine over a 14-day period. The immunoglobulin dose should not exceed 20 units per kilogram body weight. HRIG is expensive and constitutes most of the cost of post exposure treatment, ranging as high as several thousand dollars. As much as possible of this dose should be injected around the bites, with the remainder being given by deep intramuscular injection at a site distant from the vaccination site.

The first dose of rabies vaccine is given as soon as possible after exposure, with additional doses on days 3, 7 and 14 after the first. Patients who have previously received pre-exposure vaccination do not receive the immunoglobulin, only the postexposure vaccinations on days 0 and 3.

The pain and side effects of modern cell-based vaccines are similar to flu shots. The old nerve-tissue-based vaccinations that require multiple painful injections into the abdomen with a large needle are inexpensive, but are being phased out and replaced by affordable World Health Organization intradermal-vaccination regimens.

Intramuscular vaccination should be given into the deltoid, not the gluteal area, which has been associated with vaccination failure due to injection into fat rather than muscle. In infants, the lateral thigh is recommended.

Awakening to find a bat in the room, or finding a bat in the room of a previously unattended child or mentally disabled or intoxicated person, is an indication for post-exposure prophylaxis (PEP). The recommendation for the precautionary use of PEP in bat encounters where no contact is recognized has been questioned in the medical literature, based on a cost–benefit analysis. However, a 2002 study has supported the protocol of precautionary administering of PEP where a child or mentally compromised individual has been alone with a bat, especially in sleep areas, where a bite or exposure may occur without the victim being aware. Begun with little or no delay, PEP is 100% effective against rabies. In the case in which there has been a significant delay in administering PEP, the treatment should be administered regardless, as it may still be effective. Every year, more than 15 million people get vaccination after potential exposure. While this works well, the cost is significant.

Medications are usually not needed as hand, foot, and mouth disease is a viral disease that typically resolves on its own. Currently, there is no specific curative treatment for hand, foot and mouth disease. Disease management typically focuses on achieving symptomatic relief. Pain from the sores may be eased with the use of analgesic medications. Infection in older children, adolescents, and adults is typically mild and lasts approximately 1 week, but may occasionally run a longer course. Fever reducers and lukewarm baths can help decrease body temperature.

A minority of individuals with hand, foot and mouth disease may require hospital admission due to complications such as inflammation of the brain, inflammation of the meninges, or acute flaccid paralysis. Non-neurologic complications such as inflammation of the heart, fluid in the lungs, or bleeding into the lungs may also occur.

Most cases of HHV-6 infection get better on their own. If encephalitis occurs ganciclovir or foscarnet may be useful.

There are currently no Food and Drug Administration-approved vaccines for the prevention of MVD. Many candidate vaccines have been developed and tested in various animal models. Of those, the most promising ones are DNA vaccines or based on Venezuelan equine encephalitis virus replicons, vesicular stomatitis Indiana virus (VSIV) or filovirus-like particles (VLPs) as all of these candidates could protect nonhuman primates from marburgvirus-induced disease. DNA vaccines have entered clinical trials. Marburgviruses are highly infectious, but not very contagious. Importantly, and contrary to popular belief, marburgviruses do not get transmitted by aerosol during natural MVD outbreaks. Due to the absence of an approved vaccine, prevention of MVD therefore relies predominantly on behavior modification, proper personal protective equipment, and sterilization/disinfection.

Immunosuppressive therapy has been effective in halting the disease for laboratory animals.

While the general prognosis is favorable, current studies indicate that West Nile Fever can often be more severe than previously recognized, with studies of various recent outbreaks indicating that it may take as long as 60–90 days to recover. People with milder WNF are just as likely as those with more severe manifestations of neuroinvasive disease to experience multiple long term (>1+ years) somatic complaints such as tremor, and dysfunction in motor skills and executive functions. People with milder illness are just as likely as people with more severe illness to experience adverse outcomes. Recovery is marked by a long convalescence with fatigue. One study found that neuroinvasive WNV infection was associated with an increased risk for subsequent kidney disease.

Treatment (which is based on supportive care) is as follows:

Pyrimethamine-based maintenance therapy is often used to treat Toxoplasmic Encephalitis (TE), which is caused by Toxoplasma gondii and can be life-threatening for people with weak immune systems. The use of highly active antiretroviral therapy (HAART), in conjunction with the established pyrimethamine-based maintenance therapy, decreases the chance of relapse in patients with HIV and TE from approximately 18% to 11%. This is a significant difference as relapse may impact the severity and prognosis of disease and result in an increase in healthcare expenditure.