In the hamster model of yellow fever, early administration of the antiviral ribavirin is an effective early treatment of many pathological features of the disease. Ribavirin treatment during the first five days after virus infection improved survival rates, reduced tissue damage in the liver and spleen, prevented hepatocellular steatosis, and normalised levels of alanine aminotransferase, a liver damage marker. The mechanism of action of ribavirin in reducing liver pathology in yellow fever virus infection may be similar to its activity in treatment of hepatitis C, a related virus. Because ribavirin had failed to improve survival in a virulent rhesus model of yellow fever infection, it had been previously discounted as a possible therapy.

Infection was reduced in mosquitoes with the wMel strain of "Wolbachia".

Yellow fever has been researched by several countries as a potential biological weapon.

Vaccination is recommended for those traveling to affected areas, because non-native people tend to develop more severe illness when infected. Protection begins by the 10th day after vaccine administration in 95% of people, and had been reported to last for at least 10 years. WHO now states that a single dose of vaccination is sufficient to confer lifelong immunity against yellow fever disease." The attenuated live vaccine stem 17D was developed in 1937 by Max Theiler. The World Health Organization (WHO) recommends routine vaccinations for people living in affected areas between the 9th and 12th month after birth.

Up to one in four people experience fever, aches, and local soreness and redness at the site of injection. In rare cases (less than one in 200,000 to 300,000), the vaccination can cause yellow fever vaccine–associated viscerotropic disease, which is fatal in 60% of cases. It is probably due to the genetic morphology of the immune system. Another possible side effect is an infection of the nervous system, which occurs in one in 200,000 to 300,000 cases, causing yellow fever vaccine-associated neurotropic disease, which can lead to meningoencephalitis and is fatal in less than 5% of cases.

The Yellow Fever Initiative, launched by WHO in 2006, vaccinated more than 105 million people in 14 countries in West Africa. No outbreaks were reported during 2015. The campaign was supported by the GAVI Alliance, and governmental organizations in Europe and Africa. According to the WHO, mass vaccination cannot eliminate yellow fever because of the vast number of infected mosquitoes in urban areas of the target countries, but it will significantly reduce the number of people infected.

In March 2017, WHO launched a vaccination campaign in Brazil with 3.5 million doses from an emergency stockpile. In March 2017 the WHO recommended vaccination for travellers to certain parts of Brazil.

Treatment is similar to hepatitis B, but due to its high lethality, more aggressive therapeutic approaches are recommended in the acute phase. In absence of a specific vaccine against delta virus, the vaccine against HBV must be given soon after birth in risk groups.

All persons suspected of Lassa fever infection should be admitted to isolation facilities and their body fluids and excreta properly disposed of.

Early and aggressive treatment using ribavirin was pioneered by Joe McCormick in 1979. After extensive testing, early administration was determined to be critical to success. Additionally, ribavirin is almost twice as effective when given intravenously as when taken by mouth. Ribavirin is a prodrug which appears to interfere with viral replication by inhibiting RNA-dependent nucleic acid synthesis, although the precise mechanism of action is disputed. The drug is relatively inexpensive, but the cost of the drug is still very high for many of those in West African states. Fluid replacement, blood transfusion, and fighting hypotension are usually required. Intravenous interferon therapy has also been used.

When Lassa fever infects pregnant women late in their third trimester, induction of delivery is necessary for the mother to have a good chance of survival. This is because the virus has an affinity for the placenta and other highly vascular tissues. The fetus has only a one in ten chance of survival no matter what course of action is taken; hence, the focus is always on saving the life of the mother. Following delivery, women should receive the same treatment as other Lassa fever patients.

Work on a vaccine is continuing, with multiple approaches showing positive results in animal trials.

As resistance to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and streptomycin is now common, these agents have not been used as first–line treatment of typhoid fever for almost 20 years. Typhoid resistant to these agents is known as multidrug-resistant typhoid (MDR typhoid).

Ciprofloxacin resistance is an increasing problem, especially in the Indian subcontinent and Southeast Asia. Many centres are shifting from using ciprofloxacin as the first line for treating suspected typhoid originating in South America, India, Pakistan, Bangladesh, Thailand, or Vietnam. For these people, the recommended first-line treatment is ceftriaxone. Also, azithromycin has been suggested to be better at treating typhoid in resistant populations than both fluoroquinolone drugs and ceftriaxone. Azithromycin significantly reduces relapse rates compared with ceftriaxone.

A separate problem exists with laboratory testing for reduced susceptibility to ciprofloxacin: current recommendations are that isolates should be tested simultaneously against ciprofloxacin (CIP) and against nalidixic acid (NAL), and that isolates that are sensitive to both CIP and NAL should be reported as "sensitive to ciprofloxacin", but that isolates testing sensitive to CIP but not to NAL should be reported as "reduced sensitivity to ciprofloxacin". However, an analysis of 271 isolates showed that around 18% of isolates with a reduced susceptibility to ciprofloxacin (MIC 0.125–1.0 mg/l) would not be picked up by this method. How this problem can be solved is not certain, because most laboratories around the world (including the West) are dependent on disk testing and cannot test for MICs.

Control of the "Mastomys" rodent population is impractical, so measures focus on keeping rodents out of homes and food supplies, encouraging effective personal hygiene, storing grain and other foodstuffs in rodent-proof containers, and disposing of garbage far from the home to help sustain clean households . Gloves, masks, laboratory coats, and goggles are advised while in contact with an infected person, to avoid contact with blood and body fluids. These issues in many countries are monitored by a department of public health. In less developed countries, these types of organizations may not have the necessary means to effectively control outbreaks.

Researchers at the USAMRIID facility, where military biologists study infectious diseases, have a promising vaccine candidate. They have developed a replication-competent vaccine against Lassa virus based on recombinant vesicular stomatitis virus vectors expressing the Lassa virus glycoprotein. After a single intramuscular injection, test primates have survived lethal challenge, while showing no clinical symptoms.

A vaccine based on recombinant viral proteins was developed in the 1990s and tested in a high-risk population (in Nepal) in 2001. The vaccine appeared to be effective and safe, but development was stopped for lack of profitability, since hepatitis E is rare in developed countries. No hepatitis E vaccine is licensed for use in the United States.

Although other HEV vaccine trials have been successful, these vaccines have not yet been produced or made available to susceptible populations. The exception is China; after more than a year of scrutiny and inspection by China's State Food and Drug Administration (SFDA), a hepatitis E vaccine developed by Chinese scientists was available at the end of 2012. The vaccine—called HEV 239 by its developer Xiamen Innovax Biotech—was approved for prevention of hepatitis E in 2012 by the Chinese Ministry of Science and Technology, following a controlled trial on 100,000+ people from Jiangsu Province where none of those vaccinated became infected during a 12-month period, compared to 15 in the group given placebo. The first vaccine batches came out of Innovax' factory in late October 2012, to be sold to Chinese distributors.

Due to the lack of evidence, WHO did not make a recommendation regarding routine use of the HEV 239 vaccine. National authorities may however, decide to use the vaccine based on the local epidemiology.

In terms of treatment, ribavirin is not registered for hepatitis E treatment, though off-label experience for treating chronic hepatitis E with this compound exists. The use of low doses of ribavirin over a three-month period has been associated with viral clearance in about two-thirds of chronic cases. Other possible treatments include pegylated interferon or a combination of ribavirin and pegylated interferon. In general, chronic HEV infection is associated with immunosuppressive therapies, but remarkably little is known about how different immunosuppressants affect HEV infection. In individuals with solid-organ transplantation, viral clearance can be achieved by temporal reduction of the level of immunosuppression.

The rediscovery of oral rehydration therapy in the 1960s provided a simple way to prevent many of the deaths of diarrheal diseases in general.

Where resistance is uncommon, the treatment of choice is a fluoroquinolone such as ciprofloxacin. Otherwise, a third-generation cephalosporin such as ceftriaxone or cefotaxime is the first choice. Cefixime is a suitable oral alternative.

Typhoid fever, when properly treated, is not fatal in most cases. Antibiotics, such as ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, amoxicillin, and ciprofloxacin, have been commonly used to treat typhoid fever in microbiology. Treatment of the disease with antibiotics reduces the case-fatality rate to about 1%.

Without treatment, some patients develop sustained fever, bradycardia, hepatosplenomegaly, abdominal symptoms and, occasionally, pneumonia. In white-skinned patients, pink spots, which fade on pressure, appear on the skin of the trunk in up to 20% of cases. In the third week, untreated cases may develop gastrointestinal and cerebral complications, which may prove fatal in up to 10–20% of cases. The highest case fatality rates are reported in children under 4 years. Around 2–5% of those who contract typhoid fever become chronic carriers, as bacteria persist in the biliary tract after symptoms have resolved.

The two types of vaccines contain either inactivated hepatitis A virus or a live but attenuated virus. Both provide active immunity against a future infection. The vaccine protects against HAV in more than 95% of cases for longer than 25 years. In the US, the vaccine was first used in 1996 for children in high-risk areas, and in 1999 it was spread to areas with elevating levels of infection.

The vaccine is given by injection. An initial dose provides protection starting 2-4 weeks after vaccination; the second booster dose, given six to 12 months later, provides protection for over 20 years.

The vaccine was introduced in 1992 and was initially recommended for persons at high risk. Since then, Bahrain and Israel have embarked on eradication programmes. Australia, China, Belarus, Italy, Spain, and the United States have started similar programmes. The incidence of hepatitis A where widespread vaccination has been practised has decreased dramatically. In China and the United States, the incidence of hepatitis A has decreased by 90% since 1990.

In the United States, vaccination of children is recommended at 1 and 2 years of age. It is also recommended in those who have not been previously immunized and who have been exposed or are likely to be exposed due to travel. The CDC recommends vaccination against infection for men who have sex with men.

The VHF viruses are spread in a variety of ways. Some may be transmitted to humans through a respiratory route. According to Soviet defector Ken Alibek, Soviet scientists concluded China may have tried to weaponise a VHF virus during the late 1980's but discontinued to do so after an outbreak . The virus is considered by military medical planners to have a potential for aerosol dissemination, weaponizaton, or likelihood for confusion with similar agents that might be weaponized.

No specific treatment for hepatitis A is known. Recovery from symptoms following infection may take several weeks or months. Therapy is aimed at maintaining comfort and adequate nutritional balance, including replacement of fluids lost from vomiting and diarrhoea.

Lábrea fever is a coinfection or superinfection of hepatitis D or delta virus and hepatitis B (HBV). The infection by delta virus may occur in a patient who already has the HBV, or both viruses may infect at the same time a previously uninfected patient. Delta virus can only multiply in the presence of HBV, therefore vaccination against HBV prevents infection. Thus, American and Brazilian scientists have determined that the delta virusa, virus, which is a small circular RNA virus, is normally unable to cause illness by itself, due to a defect. When it is combined with HBV, Lábrea hepatitis may ensue. The main discovery of delta virus and HBV association was done by Dr. Gilberta Bensabath, a leading tropical virologist of the Instituto Evandro Chagas, of Belém, state of Pará, and her collaborators.

Infected patients show extensive destruction of liver tissue, with steatosis of a particular type (microsteatosis, characterized by small fat droplets inside the cells), and infiltration of large numbers of inflammatory cells called "morula cells", comprised mainly by macrophages containing delta virus antigens.

In the 1987 Boca do Acre study, scientists did an epidemiological survey and reported delta virus infection in 24% of asymptomatic HBV carriers, 29% of acute nonfulminant hepatitis B cases, 74% of fulminant hepatitis B cases, and 100% of chronic hepatitis B cases. The delta virus seems to be endemic in the Amazon region.

, there are about one hundred medications in development for hepatitis C. These include vaccines to treat hepatitis, immunomodulators, and cyclophilin inhibitors, among others. These potential new treatments have come about due to a better understanding of the hepatitis C virus. There are a number of vaccines under development and some have shown encouraging results.

The combination of sofosbuvir and velpatasvir in one trial (reported in 2015) resulted in cure rates of 99%.

This condition most commonly occurs after the administration of a horse origin biological agent such as equine-derived antiserum, and usually occurs 4–10 weeks after the event. Diseases that have been vaccinated against using equine-origin antiserum, resulting in subsequent Theiler's disease, include: African horse sickness, Eastern and Western Equine Encephalitis, "Bacillus anthracis", tetanus antitoxin, "Clostridium perfringens", "Clostridium botulinum", "Streptococcus equi" subspecies "equi", Equine influenza, Equine herpesvirus type 1, pregnant mare's serum, and plasma. Although it occurs sporadically, It appears to be spreadable within a premises, and there have been outbreaks occurring on farms involving multiple horses over several months. In the Northern hemisphere it is most common between August to November. It is seen almost exclusively in adult horses, and lactating broodmares given tetanus antitoxin post foaling may be more susceptible.

In assisted reproductive technology, sperm washing is not necessary for males with hepatitis B to prevent transmission, unless the female partner has not been effectively vaccinated. In females with hepatitis B, the risk of transmission from mother to child with IVF is no different from the risk in spontaneous conception.

Those at high risk of infection should be tested as there is effective treatment for those who have the disease. Groups that screening is recommended for include those who have not been vaccinated and one of the following: people from areas of the world where hepatitis B occurs in more than 2%, those with HIV, intravenous drug users, men who have sex with men, and those who live with someone with hepatitis B.

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.

Currently, no vaccine against relapsing fever is available, but research continues. Developing a vaccine is very difficult because the spirochetes avoid the immune response of the infected person (or animal) through antigenic variation. Essentially, the pathogen stays one step ahead of antibodies by changing its surface proteins. These surface proteins, lipoproteins called variable major proteins, have only 30–70% of their amino acid sequences in common, which is sufficient to create a new antigenic "identity" for the organism. Antibodies in the blood that are binding to and clearing spirochetes expressing the old proteins do not recognize spirochetes expressing the new ones. Antigenic variation is common among pathogenic organisms. These include the agents of malaria, gonorrhea, and sleeping sickness. Important questions about antigenic variation are also relevant for such research areas as developing a vaccine against HIV and predicting the next influenza pandemic.

The WHO lists 25 diseases for which vaccines are available:

1. Measles

2. Rubella

3. Cholera

4. Meningococcal disease

5. Influenza

6. Diphtheria

7. Mumps

8. Tetanus

9. Hepatitis A

10. Pertussis

11. Tuberculosis

12. Hepatitis B

13. Pneumoccocal disease

14. Typhoid fever

15. Hepatitis E

16. Poliomyelitis

17. Tick-borne encephalitis

18. Haemophilus influenzae type b

19. Rabies

20. Varicella and herpes zoster (shingles)

21. Human papilloma-virus

22. Rotavirus gastroenteritis

23. Yellow fever

24. Japanese encephalitis

25. Malaria

26. Dengue fever

In 2012, the World Health Organization estimated that vaccination prevents 2.5 million deaths each year. If there is 100% immunization, and 100% efficacy of the vaccines, one out of seven deaths among young children could be prevented, mostly in developing countries, making this an important global health issue. Four diseases were responsible for 98% of vaccine-preventable deaths: measles, "Haemophilus influenzae" serotype b, pertussis, and neonatal tetanus.

The Immunization Surveillance, Assessment and Monitoring program of the WHO monitors and assesses the safety and effectiveness of programs and vaccines at reducing illness and deaths from diseases that could be prevented by vaccines.

Vaccine-preventable deaths are usually caused by a failure to obtain the vaccine in a timely manner. This may be due to financial constraints or to lack of access to the vaccine. A vaccine that is generally recommended may be medically inappropriate for a small number of people due to severe allergies or a damaged immune system. In addition, a vaccine against a given disease may not be recommended for general use in a given country, or may be recommended only to certain populations, such as young children or older adults. Every country makes its own vaccination recommendations, based on the diseases that are common in its area and its healthcare priorities. If a vaccine-preventable disease is uncommon in a country, then residents of that country are unlikely to receive a vaccine against it. For example, residents of Canada and the United States do not routinely receive vaccines against yellow fever, which leaves them vulnerable to infection if travelling to areas where risk of yellow fever is highest (endemic or transitional regions).

Vaccines for the prevention of hepatitis B have been routinely recommended for babies since 1991 in the United States. The first dose is generally recommended within a day of birth.

Most vaccines are given in three doses over a course of months. A protective response to the vaccine is defined as an anti-HBs antibody concentration of at least 10 mIU/ml in the recipient's serum. The vaccine is more effective in children and 95 percent of those vaccinated have protective levels of antibody. This drops to around 90% at 40 years of age and to around 75 percent in those over 60 years. The protection afforded by vaccination is long lasting even after antibody levels fall below 10 mIU/ml. Vaccination at birth is recommended for all infants of HBV infected mothers. A combination of hepatitis B immune globulin and an accelerated course of HBV vaccine prevents HBV transmission around the time of birth in 86% to 99% of cases. Tenofovir given in the second or third trimester can reduce the risk of mother to child transmission by 77% when combined with hepatitis B immunoglobulin and the hepatitis B vaccine, especially for pregnant women with high hepatitis B virus DNA levels.

All those with a risk of exposure to body fluids such as blood should be vaccinated, if not already. Testing to verify effective immunization is recommended and further doses of vaccine are given to those who are not sufficiently immunized. In 10- to 22-year follow-up studies there were no cases of hepatitis B among those with a normal immune system who were vaccinated. Only rare chronic infections have been documented. Vaccination is particularly recommended for high risk groups including men who have sex with men.

There is currently no specific therapy. Intravenous fluids and treatment of the hepatic encephalopathy may help. Increasing dietary levels of branched chain amino acids and feeding low protein diets can help signs of hepatic encephalopathy, which is often accomplished by feeding small amounts of grain and/or beet pulp, and removing high-protein feedstuffs such as alfalfa hay. Grazing on non-legume grass may be acceptable if it is late summer or fall, although the horse should only be permitted to eat in the evening so as to avoid photosensitization. Due to the risk of gastric impaction, stomach size should be monitored.

Sedation is minimized and used only to control behavior that could lead to injury of the animal and to allow therapeutic procedures, and should preferably involve a sedative other than a benzodiazepine. Stressing the animal should be avoided if at all possible. Plasma transfusions may be needed if spontaneous bleeding occurs, to replace clotting factors. Antibiotics are sometimes prescribed to prevent bacterial translocation from the intestines. Antioxidants such as vitamin E, B-complex vitamins, and acetylcysteine may be given. High blood ammonia is often treated with oral neomycin, often in conjunction with lactulose, metronidazole and probiotics, to decrease production and absorption of ammonia from the gastrointestinal tract.

, no approved vaccine protects against contracting . A combination of harm reduction strategies, such as the provision of new needles and syringes and treatment of substance use, decreases the risk of in intravenous drug users by about 75%. The screening of blood donors is important at a national level, as is adhering to universal precautions within healthcare facilities. In countries where there is an insufficient supply of sterile syringes, medications should be given orally rather than via injection (when possible).

Doxycycline has been provided once a week as a prophylaxis to minimize infections during outbreaks in endemic regions. However, there is no evidence that chemoprophylaxis is effective in containing outbreaks of leptospirosis, and use of antibiotics increases antibiotics resistance. Pre-exposure prophylaxis may be beneficial for individuals traveling to high-risk areas for a short stay.

Effective rat control and avoidance of urine contaminated water sources are essential preventive measures. Human vaccines are available only in a few countries, such as Cuba and China. Animal vaccines only cover a few strains of the bacteria. Dog vaccines are effective for at least one year.

Protection is offered by Q-Vax, a whole-cell, inactivated vaccine developed by an Australian vaccine manufacturing company, CSL Limited. The intradermal vaccination is composed of killed "C. burnetii" organisms. Skin and blood tests should be done before vaccination to identify pre-existing immunity, because vaccinating people who already have an immunity can result in a severe local reaction. After a single dose of vaccine, protective immunity lasts for many years. Revaccination is not generally required. Annual screening is typically recommended.

In 2001, Australia introduced a national Q fever vaccination program for people working in “at risk” occupations. Vaccinated or previously exposed people may have their status recorded on the Australian Q Fever Register, which may be a condition of employment in the meat processing industry. An earlier killed vaccine had been developed in the Soviet Union, but its side effects prevented its licensing abroad.

Preliminary results suggest vaccination of animals may be a method of control. Published trials proved that use of a registered phase vaccine (Coxevac) on infected farms is a tool of major interest to manage or prevent early or late abortion, repeat breeding, anoestrus, silent oestrus, metritis, and decreases in milk yield when "C. burnetii" is the major cause of these problems.