Can Mosquitoes Save Lives?
In this lesson, students read about a surprising public health idea: using mosquitoes with Wolbachia bacteria to help reduce diseases such as dengue, Zika, and chikungunya.
Grammar focus: present passive, cause and effect, comparatives, and useful modals.
Grammar Cheatsheet
Present Passive
Use passive when the action is more important than the person doing it.
Mosquitoes are released into communities.
Diseases are reduced over time.
Cause and Effect
Because gives a reason. So shows a result.
Wolbachia blocks viruses, so fewer people get sick.
Mosquitoes spread disease because they carry viruses.
Comparatives
Use comparatives to compare two things.
This method is safer than heavy pesticide use.
Fewer people became sick after the program started.
Useful Modals
Can = ability or possibility.
May / might = possibility.
Wolbachia can reduce disease transmission.
Read the Story
Every rainy season, people in the city of Recife, Brazil worried about mosquitoes. The insects were everywhere — near homes, schools, markets, and parks. Many families were afraid because mosquitoes could spread dangerous diseases like dengue fever, Zika, and chikungunya.
One afternoon, Susana sat with her mother outside their apartment building. Her younger brother Mateo had recently recovered from dengue fever. He had a high fever, terrible headaches, and pain in his joints for almost a week.
“I hate mosquitoes,” Susana said. “Why can’t scientists just get rid of all of them?”
Her neighbor Francisco overheard the conversation. Francisco worked with a public health project connected to the World Mosquito Program.
“Actually,” Francisco said, “some mosquitoes may help stop disease.”
Susana laughed. “That sounds impossible.”
Francisco explained that scientists were releasing special mosquitoes carrying a natural bacteria called Wolbachia. The bacteria already exists in nature and is harmless to humans, animals, and the environment.
“When mosquitoes carry Wolbachia,” Francisco explained, “dangerous viruses cannot grow easily inside them. That means the mosquitoes are much less likely to spread diseases to people.”
Susana looked confused. “So the scientists are releasing MORE mosquitoes?”
“Yes,” Francisco replied, smiling. “But these mosquitoes help reduce disease over time.”
A few days later, Susana attended a community meeting at her school. Scientists showed charts, answered questions, and explained the project carefully. Some people in the audience were nervous at first. Others worried the mosquitoes were genetically modified.
Dr. Ramirez, one of the researchers, clarified the situation.
“These mosquitoes are not genetically modified,” she explained. “Wolbachia is a natural bacteria found in many insects around the world.”
The scientists also explained that they were not trying to eliminate mosquitoes completely. Instead, they wanted to replace dangerous mosquito populations with safer ones carrying Wolbachia.
Over the next year, small containers filled with mosquito eggs were placed around neighborhoods in Recife. Slowly, the Wolbachia mosquitoes spread through the area.
Then something surprising happened.
Hospitals reported fewer dengue cases. Schools saw fewer student absences caused by illness. Families spent less money on medical treatment. Doctors noticed that severe infections became less common.
Susana noticed changes too.
“Last year, everybody was getting sick,” she told Francisco one evening. “Now I hardly hear about dengue at all.”
Francisco nodded. “The program is helping. It’s not perfect, but it’s making a real difference.”
Susana looked at the mosquitoes flying near the streetlights.
“For the first time in my life,” she said, “I’m actually happy that some mosquitoes exist.”
Vocabulary — Matching A
Vocabulary — Matching B
Vocabulary in Context
Comprehension — Multiple Choice
Cloze A — Paragraph Practice
Click a word, then click a blank. Click 🔎 for a first-letter hint.
Cloze B — Paragraph Practice
Click a word, then click a blank. Click 🔎 for a first-letter hint.
True / False
Sequencing A
Put the story events in the correct order. Use the arrows or drag the cards.
Sequencing B
Put the story events in the correct order. Use the arrows or drag the cards.
For Example
Write one complete sentence for each prompt.
- Explain how Wolbachia works.
- Give an example of a community health project.
- Describe a disease that spreads through insects.
- Explain why some people feared the mosquito program.
- Compare this method with pesticide spraying.
Discussion / Writing
- Would you support this program in your city? Why or why not?
- Why were some people nervous about the project?
- Is it better to control mosquitoes naturally or with chemicals?
- How might climate change affect mosquito-borne diseases?
- What are the advantages of community health programs?
Role Play — Dialogue
Characters: Susana, Francisco, Dr. Ramirez, Mateo
| Speaker | Line |
|---|---|
| Susana | I still do not understand why scientists would release more mosquitoes. |
| Francisco | I understand. It sounds strange at first. |
| Mateo | Are these mosquitoes dangerous? |
| Dr. Ramirez | They are designed to carry Wolbachia, a natural bacteria. |
| Susana | Does Wolbachia hurt people? |
| Dr. Ramirez | No. It is harmless to humans, animals, and the environment. |
| Francisco | When mosquitoes carry Wolbachia, viruses do not grow easily inside them. |
| Mateo | So they are less likely to spread dengue? |
| Dr. Ramirez | Exactly. They can help reduce disease transmission. |
| Susana | Are they genetically modified? |
| Dr. Ramirez | No. Wolbachia is found naturally in many insects. |
| Francisco | The goal is not to eliminate every mosquito. |
| Mateo | Then what is the goal? |
| Francisco | The goal is to replace dangerous mosquitoes with safer ones. |
| Susana | That is a new idea for me. |
| Dr. Ramirez | New ideas often need careful explanation. |
| Mateo | If fewer people get sick, I think it is worth trying. |
| Susana | I agree. Maybe some mosquitoes really can save lives. |