Ixiaro Japanese Encephalitis Vaccine

Japanese Encephalitis Virus Spread By Mosquitoes, Pigs, and Sheep

Karen McClorey Hackett — Mon, 19 May 2025 18:42:14 +0000

Reviewer:

Japanese encephalitis virus (JEV), the causative agent of Japanese encephalitis (JE), affected an estimated 69,000 individuals in 2024.

Although JE is vaccine-preventable, it remains endemic in 24 countries and territories across Asia and Oceania, where it has a mortality rate of about 20%.

Since its identification in Japan in 1871, the transmission cycle of JEV has involved pigs and birds as amplifying hosts and mosquitoes as vectors.

However, sheep may be a factor contributing to the transmission cycle.

The results from a study published May 16, 2025, revealed that sheep are susceptible to JEV infection and develop viremia, with levels and duration comparable to those observed in pigs.

Additionally, mosquitoes fed viremic sheep blood showed an infection rate of 40.6 to 57.1%.

These researchers wrote, 'These findings indicate that sheep can serve as amplifying hosts for JEV, potentially contributing to JEV transmission and increasing the public health risk of human infections in specific regions where sheep are bred but pigs are not. This cycle exists along with the well-known pig-associated rural domestic and bird-associated wild cycles.'

In the United States, a risk assessment considered that the potential of introducing JEV into the U.S. may be highest in California due to the frequency of international arrivals from Asia and Oceania.

As of May 19, 2025, the U.S. Centers for Disease Control and Prevention (CDC) says JE survivors are estimated to live normally, but 49% of patients report neurological sequelae.

The CDC recommends JE vaccination when visiting outbreak areas. The Japanese encephalitis vaccine (IXIARO) is U.S. FDA-approved and recommended for travelers in 2025. Travel clinics and pharmacies offer vaccination appointments, which are suggested at least one month before departing abroad.

Sub Title:

Japanese Encephalitis vaccinations recommended when visiting endemic areas in May 2025

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Sheep serve as amplifying hosts of Japanese encephalitis virus

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Tuesday, May 20, 2025 - 07:15

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from Pixabay 2025

Encephalitis Prevention is Just A Vaccination Away

Karen McClorey Hackett — Sat, 03 May 2025 13:41:10 +0000

Reviewer:

Robert Carlson, MD

Encephalitis International has recently launched a global awareness campaign to emphasize the importance of vaccination against the growing threat of encephalitis, an inflammation of the brain's active tissues.

This initiative is essential since millions of international travelers visit encephalitis areas yearly.

On April 29, 2025, the campaign, 'Preventing Future Encephalitis: Climate Change and Infectious Disease,' revealed that encephalitis affects over 1.5 million people globally yearly. However, more than 70% of the population remains unaware of this serious condition, resulting in delays in diagnosis and treatment.

Dr. Ava Easton, Chief Executive of Encephalitis International, commented in a news article published by PTI that moving disease-carrying vectors like mosquitoes into new areas is compounding the risk.

"Outbreaks of vaccine-preventable diseases are increasing worldwide, putting lives at risk and exposing countries to increased treatment costs," he said.

Several countries are taking action to prevent diseases such as Japanese encephalitis (JE).

For example, India's Universal Immunisation Programme, one of the world's largest, targets 27 million infants and 30 million pregnant women annually. It provides free vaccination against 12 diseases, including Japanese Encephalitis.

India reported 1,548 cases of Japanese encephalitis (JE) from 24 states and union territories in 2024, underscoring the need for vaccinations.

In 2023, JE was described as an emerging threat in eastern central India, particularly in parts of Madhya Pradesh.

And in Australia, Queensland recorded a locally acquired human case of JE in January 2025. On March 15, 2025, local health authorities confirmed the first detection in Hemmant, an eastern riverside suburb of Brisbane.

Throughout Australia, JE vaccinations are available and offered for free.

"A vaccinated world is a safer world – each shot is a step towards freedom from preventable diseases," Dr Netravathi M, a professor at the National Institute of Mental Health and Neuro Sciences, Bengaluru, said in a news article, highlighting the long-term benefits of vaccination.

As of May 3, 2025, the U.S. Centers for Disease Control and Prevention (CDC) identified countries reporting JE cases, and the health risk varies based on destination.

JE infections cause approximately 13,600–20,400 deaths in people annually, primarily children.

The CDC writes that JE survivors are estimated to live normally, but 49% of JE patients report neurological sequelae.

As of May 2025, one Japanese encephalitis vaccine (IXIARO) is U.S. FDA-approved and recommended for travelers. IXIARO is commercially available at travel clinics and pharmacies in the U.S.

Developed by the World Health Organization, the ENCEPHALITIS: GLOBAL THREATS, TRENDS AND PUBLIC HEALTH IMPLICATIONS: A TECHNICAL BRIEF outlines key actions required to improve prevention, data collection and surveillance, diagnostics and treatment, aftercare and awareness, and research innovation in encephalitis.

Sub Title:

Encephalitis patients confirmed in Australia and India in 2025

References:

Encephalitis Technical Brief

Encephalitis International’s Research Summary

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US CDC May 2025

Japanese Encephalitis Causes Second Death in Australia's NSW

Karen McClorey Hackett — Fri, 14 Mar 2025 20:29:45 +0000

Reviewer:

Robert Carlson, MD

According to the World Health Organization (WHO), the Japanese encephalitis virus (JEV) is the leading cause of viral encephalitis in twenty-four countries.

Since 2022, when Australia's government declared a Japanese encephalitis virus (JEV) outbreak of National Significance, infected mosquitoes have spread this flavivirus into most of the country. Pigs have also served as an amplifier host.

As of March 14, 2025, JEV cases and related fatalities have been confirmed in Queensland, New South Wales (NSW), South Australia, Victoria, Australian Capital Territory, Tasmania, Western Australia, the Northern Territory, and parts of the Torres Strait region.

Unfortunately, NSW Health today confirmed a second JEV death this year.

A man in his 70s, who may have acquired JEV while visiting the Murrumbidgee River region, died in early March 2025.

This is the second death from JE acquired in Australia's southeast area this year and the fourth since the virus was first detected in NSW.

Additionally, one probable case of JE infection has been identified in a man in northern NSW. He likely acquired the infection when travelling between Moree Plains, Tamworth, and Gunnedah shires. He is now recovering at home.

This is the fifth person infected with JE in NSW this season.

NSW Health's Executive Director of Health Protection, Dr Jeremy McAnulty, said in a press release, "People need to take mosquito-borne infections seriously, especially as people start the clean-up from recent floods in an environment where mosquitos thrive."

"Standing water, like that left after mass rainfall and floods, makes for ideal breeding grounds for mosquitoes. This increases people's risk of being bitten, especially if they're working outdoors," added Dr McAnulty.

As of March 2025, the WHO says safe and effective vaccines are available to prevent JE.

In Australia, the JE vaccine is free for people who meet the eligibility criteria and is available through local General Practitioners, Aboriginal health services, and pharmacists.

In the United States, one JE vaccine (IXIARO) is U.S. FDA-approved, and the CDC recommends it for travelers visiting endemic areas in 2025.

Last year, about 650,000 people from the U.S. visited Australia, including the NSW's capital city, Sydney, with over 5 million residents. The vast majority are unprotected against JEV infections.

Furthermore, the CDC suggests other travel vaccines for Australians visiting this year. These vaccines are commercially offered at travel clinics and pharmacies in the U.S.

Sub Title:

Japanese Encephalitis is a vaccine preventable disease in 2025

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Google Maps NSW March 14, 2025

Japanese Encephalitis Virus Detected in Lake Wyangan Mosquitoes

Karen McClorey Hackett — Mon, 16 Dec 2024 18:22:46 +0000

Reviewer:

Robert Carlson, MD

Located on Australia's southeast coast, New South Wales (NSW) Health recently reminded everyone to take action to avoid virus-carrying mosquitoes this summer.

NSW Health's Executive Director of Health Protection, Dr. Jeremy McAnulty, said in a media release on December 7, 2024, that mosquitoes thrive in warm conditions, increasing the risk of mosquito-borne illnesses such as Japanese encephalitis in parts of NSW.

Almost two-thirds of NSW's population, 5.3 million, lives in the greater Sydney area along Australia's southeast coast. Over 3.7 million international travelers visited NSW in the year ending June 2024.

"Each year, NSW Health undertakes mosquito surveillance across NSW from November to April, which provides important information about when mosquito-borne disease risk is elevated," Dr. McAnulty stated.

"As part of this routine surveillance, the Japanese encephalitis virus (JEV) was recently detected in a mosquito sample in Lake Wyangan, located northwest of Griffith, on December 3, 2024."

Griffith City Council urges residents to follow the "Spray up, Cover up, Clean up, Screen up!" guidelines.

NSW Health did confirm that there have been no human cases of JEV since October 2022.

However, mosquitos in NSW can potentially carry a range of other viruses for which there are no vaccines, including Murray Valley encephalitis, Ross River, and Barmah Forest viruses.

"This is a timely reminder, both to Griffith residents and to anyone planning to enjoy the outdoors, to take protective measures this summer against mosquitoes," he said.

Australia is not alone, as over 20 countries in the WHO South-East Asia and Western Pacific Regions have endemic JEV transmission, exposing more than 3 billion people to risks of infection.

In NSW, a free JEV vaccination is available through local General Practitioners, Aboriginal health services, and pharmacists for people aged two months or older.

"Japanese Encephalitis is a serious disease with a 20-30% mortality rate," commented Crockett Tidwell RPh, CDCES, CTH, International Society of Travel Medicine Certificate in Travel Health™.

"Travelers should take time to understand their risk and mitigate that risk by preventing mosquito bites and getting vaccinated when indicated," added Tidwell, Clinical Services Manager at United Supermarkets, Lubbock, Texas.

In the United States, Valneva SE's IXIARO® (JESPECT®) inactivated, adsorbed, Vero cell culture-derived Japanese encephalitis virus vaccine are commercially available at travel clinics and pharmacies in 2024.

Note - This article was updated on Dec. 18, 2024, for headline and related local content.

Sub Title:

Australia offers vaccinations against Japanese Encephalitis

Reference:

NSW residents urged to take care this mosquito season

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Nepal's Japanese Encephalitis Outbreak Claims 17 Lives

Donald Hackett — Sat, 05 Oct 2024 11:03:39 +0000

Reviewer:

Robert Carlson, MD

Over the past few decades, Japanese encephalitis (JE) has been a significant concern in the Federal Democratic Republic of Nepal, particularly during the annual monsoon season in the Himalayan Mountains.

According to news from The Kathmandu Post, 63 people have been infected with the mosquito-borne zoonotic viral disease since June 2024. Tragically, as of September 22, 2024, 17 people, including children, have died from JE infections this year.

This ongoing JE outbreak has been detected in 29 Nepal districts, including those in the Kathmandu Valley, which is located at 5,000 feet, where virus-carrying mosquitoes are found.

Nepal's health department estimates that about 12 million people, out of a total population of 31 million, are at risk of JE in 2024. Additionally, many of the one million visitors to Nepal this year may need protection from JE.

The U.S. Centers for Disease Control and Prevention (CDC) says the JE virus is transmitted to humans through the bite of infected Culex mosquitoes. Pigs play an essential role in the natural cycle and serve as an amplifier host without suffering from disease. They maintain prolonged high-level viremia, which allows mosquitoes to get infected easily.

People are dead-end hosts in the JEV transmission cycle, says the CDC.

As of October 2024, the CDC has identified 24 countries in Southeast Asia and the Western Pacific Region reporting JE cases.

For example, in May 2024, Taiwan recorded two JE patients, including one death.

And in India, where JE has been detected since 1952, a child in Jabalpur reportedly died due to JE infection last month.

Also included in the KP news article, Dr. Abhiyan Gautam, chief of the Immunisation Section at the Family Welfare Division, stated, "We have also requested various aid agencies, including the Global Alliance for Vaccines and Immunisation, to supply JE vaccine."

Recent data from Nepal's Health Ministry show that less than 50% of the infected patients were inoculated with the JE vaccine. JE vaccination is not routinely recommended for visitors hiking to higher elevations such as Mt. Everest or spending short periods in Kathmandu.

However, JE vaccination is recommended by the CDC for expatriates living in Nepal.

While there are very few local JEV cases in the United States, the CDC cautions the millions of Californians who travel west to Asia and Pacific Ocean countries to protect themselves from infection.

In the U.S., Valneva SE's IXIARO® (JESPECT®) vaccine has been approved by the U.S. FDA and CDC for many years. This safe and effective vaccine is authorized for most children and adults traveling to Japanese encephalitis endemic areas.

As of October 5, 2024, IXIARO is available at travel vaccine clinics and pharmacies in the U.S.

Sub Title:

One million Nepal visitors may need Japanese Encephalitis vaccination or booster dose in 2024

References:

US CDC Yellow Book 2024

Nepal vaccination data dashboard 2024

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Nepal Health Dept vaccination dashboard 2024