H1N1 Flu (Swine Flu)
Learn about H1N1 Flu (Swine Flu), its reported features, relevant specialists, and questions to discuss at a medical consultation.
Also known as: Swine Flu
The sources compiled here do not cover: diagnosis, prognosis, onset, prevalence. Ask the treating doctor about these.
Understanding the condition
From: MedlinePlus, National Library of Medicine
Swine flu is an infection caused by a virus. It's named for a virus that pigs can get. People do not normally get swine flu, but human infections can and do happen. In 2009 a strain of swine flu called H1N1 infected many people around the world.
The virus is contagious and can spread from human to human. Symptoms of swine flu in people are similar to the symptoms of regular human flu and include fever, cough, sore throat, body aches, headache, chills and fatigue.
There are antiviral medicines you can take to prevent or treat swine flu. There is a vaccine available to protect against swine flu. You can help prevent the spread of germs that cause respiratory illnesses like influenza by:
- Covering your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
- Washing your hands often with soap and water, especially after you cough or sneeze. You can also use alcohol-based hand cleaners.
- Avoiding touching your eyes, nose or mouth. Germs spread this way.
- Trying to avoid close contact with sick people.
- Staying home from work or school if you are sick.
Understanding terms used in the source
These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.
- Headache
- Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.
- Fatigue
- A subjective feeling of tiredness characterized by a lack of energy and motivation.
Which doctor should you see?
The suggested department for discussing H1N1 Flu (Swine Flu) is Infectious Diseases, with a general physician / infectious disease specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.
This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.
How to prepare for an assessment
Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.
Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.
- Which exposure or organism is suspected, and what evidence would confirm it?
- Are precautions, vaccination or advice for close contacts relevant to this infection?
- What should happen if symptoms worsen or do not improve as expected?
Treatment discussions and follow-up
Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.
Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.
The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.
When to seek emergency help
Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.
Questions about the diagnosis and everyday life
If H1N1 Flu (Swine Flu) is only suspected, ask what other explanations are being considered and what would distinguish them. Similar symptoms can occur in different conditions. A clinician should interpret the pattern of findings, the examination and any investigations together; reading a list of features cannot establish whether this diagnosis fits.
If the diagnosis is already confirmed, ask which features are relevant to you and which are only possible features described in a broader group. Check whether changes in daily activities are needed, whether another health problem affects the plan, and whether a written summary would help other clinicians understand your care.
When comparing care options, ask about the expected benefit, the likely time needed to assess improvement, the burdens of treatment, and reasonable alternatives. If costs, travel or availability make a plan difficult, raise this during the consultation so the team can discuss a workable follow-up arrangement. Do not assume that a specialist test or treatment described in an overseas source is routinely available locally.
This condition is usually assessed by an infectious disease specialist. Every profile shows the doctor’s registration and what has been checked.
All infectious diseases conditions →
Sources
- MedlinePlus, National Library of Medicine — H1N1 Flu (Swine Flu) — Public-domain health-topic summary
- Human Phenotype Ontology Consortium — terminology definitions — HPO licence; definitions reproduced without alteration
- Government of India — Emergency Response Support System — Official reference for India emergency number
Source: MedlinePlus, National Library of Medicine. Orphadata Science: Free access data from Orphanet. © INSERM 1999; July 2026 data, CC BY 4.0. This product uses the Human Phenotype Ontology (hp/releases/2026-09-01). Only sources listed for this article apply. Source material has been selected and arranged; HPO definitions are reproduced without alteration. No source organisation endorses this compilation. Köhler S et al. The Human Phenotype Ontology project: linking molecular biology and disease through phenotype data. Nucleic Acids Research 2014;42(D1):D966–D974. doi:10.1093/nar/gkt1026.
General information, not advice about your situation. Errors can be reported through the corrections process. Reference TDI-C-1069.