Delayed-type hypersensitivity (DTH) occurs more than 12 hours after exposure to certain allergens – with maximal reaction time between 48 and 72 hours.

The virus spread worldwide resulting in the COVID-19 pandemic.

Quelling reaction, also known as Neufeld reaction, is a biochemical reaction used to visualize/detect bacterial capsules, which if positive, appear enlarged. Streptococcus pneumoniae, Klebsiella pneumoniae, Neisseria meningitidis, Bacillus anthracis, Haemophilus influenzae, Escherichia coli, and Salmonella.

The collection of urine is done to diagnose infection in the urinary system. Clinical syndromes such as UTIs, urethritis, ureteritis, asymptomatic bacteriuria, cystitis, urethral syndrome, pyelonephritis, etc.

Bronchitis is an infection of the main airways of the lungs (bronchi) resulting in inflation and irritation of the bronchus. It can be divided into two types based on the durability of the infection.

Pneumonia is the inflammation of the lower tract involving the lung's airways and supporting structures. Once the pathogens have successfully invaded the lung, it affects the alveolar spaces and their supporting structure, the interstitial and the terminal bronchioles causing disease.

The purpose of a vaccine is to induce an immune response and establish long-term immunological memory which protects if the virus ever invades the body.

Bio-terrorismBio-terrorism is the deliberate use of microbial agents or their toxins as weapons against non-combatants outside the settling of armed conflict (COHEN).

Lower Respiratory Tract Infections (LRTI) is the infection of the bronchi, bronchiole, and alveoli by many species of bacteria, viruses, and fungi.

Urinary Tract Infection (UTI) is characterized as being upper (U-UTI) or lower (L-UTI) based on the anatomical location of the infection. L-UTI encompasses the bladder and urethra and may affect the urethra (urethritis), the bladder (cystitis), or the case of the male prostate (prostatitis).