Scenario-Tosari Virus Fever

Print Friendly, PDF & Email

“Have you read these reports? This looks pretty bad.”

Female scientist using microscope to analyze samples.
Analyzing microscopic samples. Image: CDC

You and your colleague, Maria, just got some information about a new assignment.  It looks like you are both on your way to Bangladesh to investigate the emergence of a disease outbreak    occurring there.

In your work with the National Institutes of Health (NIH) you have investigated many different diseases and outbreaks. Each one is a challenge, but this one seems to be particularly disturbing.

You have just skimmed the first few paragraphs, and what you read is chilling.

“You know what this looks like, right? Are you thinking the same thing? Tosari?”

Maria looks pretty grim. “Yes, I thought the same thing.  But, how? We haven’t had an outbreak of Tosari in years and that was 2,100 miles from Bangladesh! How is it just popping up over 2,100 miles away? And in humans right off the bat?”

“Ok,” you say to Maria, “Let’s go through this info and then we can start to plan our next moves. It looks like we can do a lot of prep work before we even get there. The field investigators with the Bangladesh Infectious Disease Unit in Dhaka have sent a few patient interviews.  Maybe we can sort things out and get some clues to how this virus—if it’s even Tosari—is being spread this time. ”


Map showing the location of Bangladesh
Location of Bangladesh. Bordered by India and Myanmar in South Asia.

After reading the briefing information and data, you look at Maria and hope the preliminary reports are wrong. The reports—according to the symptoms— seem to indicate that an outbreak of Tosari Virus Fever is occurring in Bangladesh. You know the country is a hotbed of viral outbreaks. The environment, recurrent severe weather events, poverty, and social and cultural practices play important roles in fostering the spread of disease, but they’ve never had Tosari before.

Tosari Fever is a re-emerging disease that seems likely to be a major infectious disease given its rapid increase in the number of cases elsewhere in the world. If this is Tosari, you both know that time is a critical factor in containing the outbreak, but without known transmission methods or an effective vaccine, there is little hope of preventing or containing the disease quickly.

Of particular concern is the high mortality, or death rate, for this outbreak. Tosari Fever is an incurable, deadly disease. Victims become ill with a high fever and 48 hours later, they fall into a coma. Within one week, 7 out of 10 have died. The last Tosari outbreak, in Indonesia over 5 years ago, did not have this high mortality rate. What is happening in Bangladesh and how did the virus get there?

Investigators with the Bangladesh Infectious Disease Unit have already sent you some patient data and interviews so that your team can identify clues that may lead to the transmission method. Somewhere, embedded in the patient interviews are the clues you need in order to identify the transmission method of the Tosari virus in Bangladesh. You know that identifying the transmission method is key to prevention and containment. You also know that a disease can be transmitted in more than one way; identifying each transmission method is important.

The outbreak seems to be occurring in several locations. Cases have been reported in Faridpur, Tangail, Baliakandi, and other small villages and towns on the Padma and Chandana Rivers.  Cases have also been reported in the capital city of Dhaka, but those have involved family members who have come to take care of relatives who have been brought to the Dhaka hospital.

Given the ease and frequency of travel in today’s world, health officials at NIH, the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) are concerned that the deadly virus may spread to other countries.

Bangladesh is about as large as the state of Iowa. It is one of the poorest yet densely populated countries in the world. It has over 700 rivers and the world’s largest delta, the Bengal Delta, just to its south. The country often floods in the monsoon season which lasts from June to October. Natural disasters, such as floods, cyclones, and tornadoes occur every year. Severe floods are not uncommon.

You love your work and the travel to exotic locations. You have visited Bangladesh before; the people are wonderful and the country is beautiful! Hopefully, you can quickly resolve this outbreak and save lives.

Your Task

Review the Tosari Virus Fever information and patient interviews for clues to figure out how this disease may be transmitted. Knowing how the disease is transmitted will help identify prevention and control strategies and may possibly allow the outbreak to be controlled quickly.  You know you have to find answers quickly and accurately for your briefing to your colleagues at the NIH and CDC and for public health officials in Bangladesh anxiously awaiting some guidance.

    Use the following Guiding Questions to help you determine key information about the Tosari virus and to help you prepare your report to the NIH and CDC. Your report should include information about the virus, most likely transmission methods, and prevention and control measures that could limit and/or stop the outbreak from spreading. Be able to support your recommendations with evidence and information on viral diseases and transmission methods.

Guiding Questions:

1) What are the possible transmission methods for Tosari Virus Fever given the information in the description and the patient information and interviews? After reading the patient interviews, make a list of every possible transmission method based on information provided.






2) Of course, no official decision will be made until scientific evidence from laboratory testing is available.  However, you can now narrow the transmission methods you listed to the most likely methods. Give your reasons for eliminating any transmission method.








3) How could each of the most likely transmission methods be tested to find out if it could be spreading the disease in Bangladesh?   







4) Which transmission method is your top choice?  You may list more than one if the patient interviews suggest more than one method, but only if you think the two are equally responsible for the spread of infection. Defend your choice.




 5) There are more clues in patient interviews than just symptoms and locations. Did you notice anything that a few of the patients have in common?  Could this possibly be important to figuring out how to stop the spread of this disease?