According to the Lancet Global Burden of Disease Study, the awareness of common communicable diseases in different countries is acutely low, resulting in almost 27.5% of deaths in India. Hence, it is essential to gather knowledge of communicable diseases, their symptoms, causes and methods to prevent them.

A communicable disease is a contagious type of ailment spread from one individual to another through blood and bodily fluids, lack of awareness, infection by any harmful insects, or coming in contact with any airborne virus.

The extensive research and experiments from real-life cases show approximately 80 types of infectious diseases found in the world. The list of communicable diseases includes some life-threatening ailment, which is:

• Ebola
• Rabies
• Tuberculosis
• West Nile Virus
• Diseases through sexual transmission like HIV, gonorrhoea, etc
• Hantavirus
• Hepatitis A
• Hepatitis B
• Measles
• CRE
• Pertussis
• Enterovirus D68, etc.

Each infection caused by a virus or bacteria has its distinct symptoms; however, there are a few general symptoms of common communicable diseases which are as follows:

• Chronic Diarrhoea
• Fatigue and viral fever
• Muscle cramping
• Coughing

Apart from this, there are a few chronic symptoms that require immediate attention by a medical practitioner, such as:

• Dark urine
• Pruritus
• Splenomegaly
• Posterior cervical lymphadenopathy
• Arthralgias and myalgias, etc. 

Individuals experiencing such symptoms require proper planning and evaluation of the type of communicable disease. Therefore, the concerned doctor went extra-hand to analyse the reason for these infections and prescribed the necessary treatment accordingly.

As per various medical reports, the leading causes of infections in communicable diseases are the attack of pathogens like fungi, bacteria, viruses, and protists (algae). Each pathogen affects the human body differently and is explained in this context.

1. Bacteria

These microscopic organisms have singular cell compositions and exist even in the human body. While countless good bacteria help the body build suitable enzymes, there are bacteria like Salmonella and Escherichia coli responsible for infection in the digestive system. This contamination is mostly unwashed fruits and vegetables and raw meats. Individuals suffering from infections caused by these bacteria face symptoms such as headache, fever, abdominal cramps, diarrhoea, etc.

Another life-threatening bacterial infection is tuberculosis. This infection affects the lungs arising in some chronic symptoms like:

• Loss of appetite
• Sudden and unintentional weight loss
• Body complications like fever, sweats, night chills, prolonged cough

2. Viruses

Viruses are pathogens capable of genetic mutations and lack a cell structure. They enter the human body's cells and use their machinery to respond and spread. Some of the lethal viruses that top the list of communicable disease are: 

Influenza: This type of virus attacks the respiratory system in the human body and has some prominent symptoms such as

• Fatigue
• Fever
• Sore throat
• Muscle and body cramps
• Continued cough and runny rose
• Formation of mucus in lungs and air pipe
• Breathing issues

The influenza virus affects people when they contact people with the same influenza virus. 

Rhinovirus: People infected with rhinovirus are caught with the common cold and experience generic symptoms like sore throat, headache and stuffy nose. However, this group of viruses is infectious as it can be spread by inhaling infected droplets in the air from the cough or sneeze of different individuals. 

HIV (Human Immunodeficiency Virus): This deadly virus destroys the natural ability of the body to fight infections that are generally transmitted through infected blood and other bodily fluids. Some of the chronic symptoms of HIV are as follows:

• Swollen lymph nodes
• Fever and chills
• Mouth sores
• Body and muscle cramps
• Rash 

The primary step of diagnosing this type of infectious disease involves conducting HIV tests. As per doctors, there is no permanent solution to HIV; however, certain medications have proved to control the virus. Therefore, people searching for "what are communicable diseases” come to know about HIV/AIDs as these infectious diseases are more deadly than the rest.

3. Fungi

Fungi affect in the form of yeasts and mould in the skin and mostly in the mucus membrane. This is a type of organism that can occur in any part of the body as the following infections:

• Athlete’s Foot: As the name suggests, this type of infection attacks the skin on the feet, leaving soreness, rash and itchiness in between the toes. In most cases, an athlete’s foot occurs due to contact with someone infected with the same fungus.
• Ringworm: Ringworm is the most common type of fungus infection on the skin, which occurs as a red ring-shaped rash resulting in a scaly and itchy skin surface. This type of communicable disease occurs during close contact with a person with the same fungus infection or sharing the same towel, etc.
• Protists: These are single cellular and microscopic organisms which are parasitic primarily in nature. It means these use the nutrients of another organism to survive and grow. One of the significant examples of parasitic protists is Plasmodium which acts as a cause of tropical diseases like malaria. For example, the prominent symptoms of malaria are vomiting, diarrhoea, muscle pain, high fever and headaches, etc.

In all these symptoms of communicable diseases, it is mandatory to seek medical help to cure and control the growth of the virus, fungi, bacteria and protists.

According to numerous studies conducted under the supervision of specialist doctors, the essential risk factors like water, hygiene and sanitation, environment and public health systems, living conditions, nutrition, etc., trigger communicable diseases in most individuals.

Furthermore, the lack of healthcare facilities and shortage of awareness and surveillance are the factors that influence risk factors of communicable diseases.

According to medical research on communicable diseases, vaccines are considered the most effective method of combating the virus or bacteria. Vaccines work as a shield as the inactive virus in the vaccines helps create antibodies that kill the active infectious virus. Different types of communicable diseases require specific treatments such as:

• In case of bacterial infections, doctors mainly prescribe courses of strong antibiotics to kill the bacteria and stop them from re-building.
• The infected person is prescribed over-the-counter antifungal injections or drugs for fungal infections. Based on the severity of these infections, doctors prescribe oral or topical medicines.

With the advancement of medical science, the treatment for communicable disease has become more effective. Hence, people noticing any prominent symptoms must not delay approaching medical assistance.

The prevention of communicable disease involves adopting and changing a few lifestyle habits, which include the following:

• Maintain cleanliness and disinfectant of the commonly used home and kitchen area, doorknobs, tables, etc.
• Avoid eating stale or rotten food items.
• Washing hands with soap/hand wash at frequent intervals.
• Maintaining excellent hygiene while cooking food and storing kitchen appliances or staples.
• Getting necessary vaccinations
• Taking the preventive medication for anti-malarial in a mosquito-infested area

The biggest prevention of communicable disease can be initiated through immunisation. In addition to this, the health experts also advise maintaining a distance around wild animals as germs can be spread from them.