Infectious diseases are caused due to invasion of the body tissues by microorganisms such as bacteria, fungus, virus, and parasites. Infections are one the leading causes of death world-wide. Day- by-day it is getting more difficult to manage infections as these pathogens have acquired resistance to the commonly used antibiotics. Approximately, half of all deaths all over the world caused by infectious diseases each year can be attributed to these three diseases: tuberculosis, malaria, and AIDS. These diseases cause over 300 million illnesses and more than 5 million deaths each year.
Organisms causing infection
The microorganisms or the pathogens which cause disease are classified as bacteria, virus, fungus and parasites.
|Bacteria||Streptococcus, Staphylococcus aureus|
|Virus||Dengue virus, Influenza virus, Rotavirus, Human Papilloma Virus|
|Fungus||Ringworm, Candida Albicans|
|Parasites||Giardia, Plasmodium falciparum, Pork tapeworm|
Modes of transmission
Infection can be acquired in many ways and its mode of transmission are as follows:
Direct contact: Infection can occur when a healthy person comes in direct contact with a person having the infection
- Person-to-person contact: Infection can be acquired by touching, kissing, or through sexual contact with an infected person. Eg: Human Papilloma virus infection
- Droplet infection: Infection can be caused when a healthy person inhales the droplets of saliva, sputum or nasal discharge of an infected person. Eg: Staphylococcus Aureus infection
- Mother to unborn: An infected mother may pass her infection to the unborn baby through the placenta. Eg: HIV infection
Indirect contact:Indirect transmission occurs when an infection gets transmitted from infected person to a healthy person through an intermediate or carrier. Types of indirect contact include:
- Airborne transmission A healthy person may catch the infection when he inhales the contaminated air. Eg: Flu
- Contaminated water and food: Consuming contaminated foods or sharing the food with a person having infection may lead to infection in an otherwise healthy person. Eg: Typhoid
- Insect and animal bites: Insects and animals carry large number of microorganisms. Therefore, insect or animal bites can result in infection. Eg: Malaria
- Blood transfusion: Infections can be transmitted when the blood of an infected person is transfused in to a healthy person. Eg: Hepatitis B, HIV/AIDS
Signs and symptoms
Disease causing microorganisms or pathogens trigger the immune system which produces a defensive action. Signs and symptoms of infection may vary depending upon the organism causing the infection. Some of the common symptoms of infectious diseases are as follows:
- Muscle Aches
Diagnosis of an infection
Laboratory tests help to detect the presence of infection, the causative organism and determine the progression of infection. The various types of lab tests for infection include:
- Blood test: White blood cells (WBC) fight infection. Therefore, an increased level of WBC’s is indicative of infection. The normal level of WBC is 4,500 to 11,000 cells per microliter (cells/mcL).
- Urinalysis: The urine dipstick is done to check for infection. Presence of nitrites or leukocyte esterase in urine may be a sign of a urinary tract infection. Detection of bacteria or yeast during the microscopic evaluation of the urine sample also suggests infection.
- Stool examination: A microscopic evaluation of a stool sample can help in detection of organisms causing intestinal infections.
- Throat swabs: Throat swab refers to a sample of tissue which is taken from the back of your throat. When the respiratory system examination and the blood tests indicate respiratory infection, throat swabs are cultured to identify the organism causing the infection. The infection which can be detected by throat swab culture include Candida albicans, Group A streptococcus and Neisseria meningitidis
- Lumbar puncture: Lumbar puncture can help in detecting serious infections such as meningitis, encephalitis and syphilis. In this test, a thin needle is inserted into your spinal canal and a small sample of cerebrospinal fluid(CSF) is obtained. This CSF sample is sent for analysis. Indicators of infection in the CSF sample:
- Appearance: Cloudy, yellow or pink color of CSF is indicative of infection.
- Protein: Increased levels of total protein (< 45mg/dL) may indicate infection or another inflammatory condition.
- White blood cells: Elevated WBC’s in CSF indicate infection. Normally, CSF contains up to 5 mononuclear leukocytes (white blood cells) per microliter.
- Glucose: A low level of glucose in CSF may indicate infection.
- Pathogens: Presence of bacteria, viruses, fungi or other microorganisms indicates infection.
- Imaging tests: Imaging tests such as CT and MRI can help to rule out other conditions that may cause the patient’s symptoms.
- Biopsy: During biopsy, a sample of the infected tissue is collected and evaluated to detect the causative organism.
Once the specific causative organism is determined, the health care provider can prescribe the specific antibiotic, antiviral, anti-parasitic or anti fungal drugs to treat the infection.
- Wash your hands with soap especially before eating and after using toilet.
- Eat properly cooked meat to avoid parasitic infections.
- Do not share personal items such as tooth brush, towels, underwear, and towels.
- Practice safe sex measures such as using condoms and diaphragms to avoid sexually transmitted diseases.
- Use a face mask while in crowded places to prevent air borne infections
- Isolate yourself if you are suffering from any infectious disease.
- Drink clean and purified water to prevent water- borne infections.
- Wash fruits and vegetables thoroughly before eating to remove germs.
Why choose Apollo Diagnostics?
We have the expertise of 34 + years in healthcare. Our labs are equipped with EQUAS (External Quality Assurance System) and loaded with full automated machines to ensure error free reports, with a quick turnaround time, and at an affordable price. For your convenience, we offer free home collection of samples.
- Infectious diseases. http://www.mayoclinic.org/diseases-conditions/infectious-diseases/symptoms-causes/dxc-20168651. Accessed on: 25/9/2017
- Throat Culture. http://www.webmd.com/oral-health/throat-culture#1. Accessed on- 28.09.17
- Human diseases and conditions: http://www.humanillnesses.com/General-Information-and-Infectious-Diseases-A-Co/Laboratory-Tests.html. Accessed on 25/9/2017
- Urinalysis Results.http://www.mayoclinic.org/tests-procedures/urinalysis/details/results/rsc-20255397. Accessed on 28/09/17
- Common Infectious Diseases Worldwide. https://www.infoplease.com/science-health/health/common-infectious-diseases-worldwide. Accessed on 28/09/17