Viral Infections

Bacterial and viral infections can both cause symptoms such as malaise, fever, and chills. It can be difficult to distinguish which is the cause of a specific infection. It’s important to distinguish, because viral infections cannot be cured by antibiotics.

For infection to occur in a human, the chain of events must happen. Infections do not occur by chance but involve many factors. The chain of events involves several steps which include the infectious agent, reservoir, susceptible host, portal of entry, mode of transmission and portal of exit. Each of the links must be present in a chronological order for an infection to develop. Understanding these steps helps health care workers target the infection and prevent it from occurring in the first place. Each one of these links has an integral role in infection

Swollen Lymph Nodes (Lymphadenopathy)

Lymphadenopathy is a term meaning “disease of the lymph nodes.” It is, however, almost synonymously used with “swollen/enlarged lymph nodes”. It could be due to infection, auto-immune disease, or malignancy.

Mononucleosis

The classical symptoms of mononucleosis are a sore throat, fever, fatigue, weight loss, malaise, pharyngeal inflammation, petechiae and loss of appetite. Common signs include lymphadenopathy (enlarged lymph nodes), splenomegaly (enlarged spleen), hepatitis (refers to inflammation of hepatocytes – cells in the liver) and hemolysis (the bursting of red blood cells). Older adults are less likely to have a sore throat or lymphadenopathy, but are instead more likely to present with hepatomegaly (enlargement of the liver) and jaundice. Rarer signs and symptoms include thrombocytopenia (lower levels of platelets), with or without pancytopenia (lower levels of all types of blood cells), splenic rupture, splenic hemorrhage, upper airway obstruction, pericarditis and pneumonitis. Another rare manifestation of mononucleosis is erythema multiforme.

Lymphadenopathy (swollen lymph nodes)

Lymphadenopathy is a term meaning “disease of the lymph nodes.” It is, however, almost synonymously used with “swollen/enlarged lymph nodes”. It could be due to infection, auto-immune disease, or malignancy.

Inflammation of a lymph node is called lymphadenitis. In practice, the distinction between lymphadenopathy and lymphadenitis is rarely made. (Inflammation of lymph channels is called lymphangitis.

Infections

An infection is the detrimental colonization of a host organism by a foreign species. In an infection, the infecting organism seeks to utilize the host’s resources to multiply, usually at the expense of the host. The infecting organism, or pathogen, interferes with the normal functioning of the host and can lead to chronic wounds, gangrene, loss of an infected limb, and even death. The host’s response to infection is inflammation. Colloquially, a pathogen is usually considered a microscopic organism though the definition is broader, including parasites, fungi, viruses, prions, and viroids. A symbiosis between parasite and host, whereby the relationship is beneficial for the former but detrimental to the latter, is characterised as parasitism. The branch of medicine that focuses on infections and pathogens is infectious disease. “When infection attacks the body, anti-infective drugs can help turn the tide of battle. Four types of anti-infective drugs exist: antibacterial, antiviral, antitubercular, and antifungal.

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