Medindia
Advertisement

What Prompts Influenza Virus To Cause Pneumonia Infection?

by Rishika Gupta on December 12, 2018 at 12:34 PM

 What Prompts Influenza Virus To Cause Pneumonia Infection?
Inner mechanisms of cells that trigger pneumonia in humans are being studied here in this study. It has been found that the influenza virus impairs our body's protective response and thereby facilitates the start of pneumonia.

The situation is relatively common, especially in winter. You come down with the flu, which lasts longer than usual. A few days later, you discover you have pneumonia.
Advertisement


The relationship between influenza and pneumonia has long been observed by health workers. Its genetic and cellular mechanisms have now been investigated in depth by scientists in a study involving volunteers and conducted in the United Kingdom.

Published in the journal Nature Immunology, the paper describes for the first time a cellular mechanism that controls the proliferation of pneumococci - the Streptococcus pneumoniae bacteria that cause pneumonia - and their movement from the nose to the lungs. It also reports that in humans, the inflammation caused by the influenza virus impairs the innate immune control of pneumococci.
Advertisement

The study was performed by scientists at the Center for Research on Inflammatory Diseases - CRID, a Research, Innovation, and Dissemination Center - RIDC funded by São Paulo Research - FAPESP, and the Liverpool School of Tropical Medicine (LSTM) in the UK. It was supported by the Bill & Melinda Gates Foundation, the UK Medical Research Council (MRC), and the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES), as well as FAPESP.

"Based on our understanding and analysis of the cellular, genetic and immune response mechanisms, we were able to prove that most flu-related deaths are due to post-flu pneumonia rather than to the influenza virus itself," said Helder Nakaya, a researcher affiliated with CRID and a coauthor of the paper.

The main reason, according to the results of the study, is that influenza virus silences the organism's innate immune response, in particular inhibiting the action of monocytes - the main type of leukocyte or white blood cell responsible for expelling foreign bodies such as viruses and bacteria.

To conduct the study, the researchers recruited volunteers to be inoculated with attenuated influenza virus and pneumococcus. This procedure is permitted in the UK.

No volunteers suffered from pneumonia during the study.

Researchers on the Brazilian side analyzed and interpreted genetic and cellular data using CEMiTool bioinformatics software developed at the University of São Paulo's Pharmaceutical Science School (FCF-USP) with FAPESP's support under the aegis of its Young Investigators grant program.

"The software tool enabled us to analyze the interaction among the various genes in a very large number of samples, given that 140 volunteers took part in the study," Nakaya said.

Journey of pneumococcus

Live attenuated influenza viruses were obtained from the flu vaccines (Fluenz/Flumist) administered every winter in the UK. Three days after receiving the flu virus, the volunteers received pneumococcus via nasal spray. Blood samples, nasal swabs and nasal cells from the volunteers were analyzed throughout the study, which lasted an entire winter.

"In order for pneumonia to develop, the bacterium must be in the lungs. This same bacterium can live in the nose for a long time without causing symptoms, especially in healthy adults. For some reason, however, especially in more vulnerable patients, the bacterium travels from the nose to the lungs. Our study focused precisely on the mechanisms that clear the bacteria from the nose and prevent it from traveling to the lungs, and on how influenza virus alters this process," said Daniela Ferreira, a professor at LSTM and principal investigator for the study.

The findings showed that the number of bacteria in the nose increased significantly because of the influenza virus. "Another important point is that excessive multiplication of pneumococcus heightens the patient's predisposition to transmit it to other people," Ferreira said. "So there are two problems: an increase in individual susceptibility to pneumonia, and an increase in transmission of pneumococcus in the general population."

The bacteria multiply in the nose when the influenza virus impairs the immune response by inhibiting monocyte antibacterial activity.

"We analyzed the genes and mechanisms involved in the bacterium's journey to the lungs. We also identified biological markers that are more expressed in an individual with the virus and uncontrolled bacterial infection. In future we'll be able to use all this information to develop better vaccines and therapies," Ferreira said.

Different in humans

The mechanisms of the immune response to colonization by pneumococcus have been thoroughly studied in mice but remain poorly understood in humans. Using for the first time a human experimental challenge model with the attenuated flu virus and pneumococcus, the researchers discovered that in humans, unlike mice, nasal bacterial infection leads quickly to the activation of neutrophils, another type of lymphocyte always present in the human nose, and to the recruitment of monocytes, which clear the nostrils of bacteria by rupturing their vesicles (lysis) — neutrophil recruitment results in control of the bacteria in mice, instead of monocyte recruitment.

This finding "underlin[es] the importance of confirming mouse findings with human data," the authors stress in the article.

Another finding was that the live attenuated influenza vaccine could be used to control pneumonia, which is a major global health problem and kills more children under five than any other disease. It is also particularly dangerous to the elderly and people with chronic lung disease, immunosuppression, and viral coinfection.

"The most important point about this entire process is that people need to be immune to flu. The flu vaccine also proved beneficial to avoiding pneumonia," Ferreira said.

The researchers are now analyzing the converse situation when infection by the bacteria occurs first and is followed by influenza virus infection.

Source: Eurekalert
Advertisement

Advertisement
News A-Z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
News Category
What's New on Medindia
'Hybrid Immunity' may Help Elude COVID-19 Pandemic
Stroop Effect
Plant-Based Diet may Reduce the Risk of COVID-19
View all

Medindia Newsletters Subscribe to our Free Newsletters!
Terms & Conditions and Privacy Policy.

More News on:
Chicken Pox Hib Vaccine Pneumonia Shigellosis Flu Swine Flu Reye’s Syndrome Q Fever Silicosis Respiratory Distress Syndrome 

Recommended Reading
Vaccine Strategy Induces Antibodies That Neutralize Diverse Influenza Viruses
In the blood samples of people who had received a vaccine against H5N1 influenza, scientists ......
Influenza Virus is Protected by Mucus Regardless of Humidity: Study
Humidity won't hamper the spread of influenza virus, stated study. The finding highlights the ......
Early Life Exposure To Influenza Virus May Not Assure Immunity
Exposure to pandemic influenza early in life can increase the risk for mortality during subsequent ....
Hong Kong Bans Live Poultry Sale Due to Avian Influenza Virus
The presence of H7N9 virus was confirmed after an analysis of some samples taken from the Yan Oi ......
Chicken Pox
Chicken pox is an acute and highly contagious viral infection caused by the varicella zoster virus....
Hib Vaccine
The Hib vaccine protects children against infections like meningitis and pneumonia that are caused b...
Pneumonia
Pneumonia is a lung infection that can be caused by a bacteria or a virus. It causes inflammation of...
Q Fever
Q Fever takes its origin from word “query” and is caused by bacteria Coxiella burnetii that infects ...
Respiratory Distress Syndrome
ARDS is a lung condition where the patient suffers from sudden breathlessness, low blood oxygen leve...
Reye’s Syndrome
Reye's syndrome is a medical emergency chiefly affecting children and teenagers and is marked by the...
Shigellosis
Shigellosis or Bacillary Dysentery is a common cause of gastro-enteritis worldwide and can cause blo...
Silicosis
Silicosis is a lung disease caused by inhalation of crystalline free silica dust. It is characterise...
Swine Flu
Swine flu, a type of influenza caused by a new strain of the H1N1 Type A influenza virus has origina...

Disclaimer - All information and content on this site are for information and educational purposes only. The information should not be used for either diagnosis or treatment or both for any health related problem or disease. Always seek the advice of a qualified physician for medical diagnosis and treatment. Full Disclaimer

© All Rights Reserved 1997 - 2021

This site uses cookies to deliver our services. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Use