Infectious Agents

Severe myalgia seen in Dengue fever is named “break-bone fever”. Other presentations are sudden onset of fever, headache, retroorbital & back pain

Leishmenia is a hemoglagellete

Explanation: Klebsiella is responsible for developing penumonia in a chronic alcholic person

Endospore formation is seen in Clostridium difficile

“Ground itch,” a pruritic papule or vesicle, can occur at the site of entry of the ancylostoma larvae into the skin.

Explanation -
Reactive arthritis occurs after following infection -
Genitourinary tract ( Chlamydia) 
Gastrointestinal tract ( Shigella,Salmonella,Yersinia,Camphylobacter) 

Explanation: Malaria is caused primarily Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum. Among them Plasmodium vivax is most widely distributed and P. falciparum causes the most serious disease.

S. hematobium causes bladder cancer

Explanation: Ascariasis causes eosinophilia

Candidiasis infection is thick curdy.

Explanation: Ascaris lumbricoides is known as the “giant roundworm.” The adults are the largest intestinal nematodes, often growing to 25 cm or more.

Explanation: Although most clinical syndromes are caused by zoonotic transmission of parasites from animals to humans through phlebotomine sandfly vectors

Leishmania is a hemoflagellete

Explanation: Secondary pulmonary tuberculosis classically involves the apex of the upper lobes of one or both lungs

Signet ring is present in P. falciparum

Explanation: Other causes of Atypical pneumonia are : Psittacosis, Q fever, Legionella, Mycoplasma pneumoniae.

Explanation :
Bacterial spores are small oval or spherical structures that are very resistant to high temperatures, radiation, desiccation, and chemical agents.
When they are formed intracellularly, they are called endospore.
The bacterial cell producing spore is called vegetative cell.

Explanation: P. vivax and P. ovale may persist in liver cells as dormant forms, hypnozoites, capable of developing into merozoites months or years later.

Common organism of meningitis in neonate is E. coli

Explanation: proteus produces swarming growth. & produces alkaline urine that leads to stone formation.

Explanation: RDT-Malaria, NS1-Dengue, rK39 for Kala-azar

Ancylostoma duodenale passes thrpugh lung in its life cycle

Sandfly is vector for kala-azar

Non capsular Organisms - Cryptosporidium spp.

All other are lesion in neurosyphilis

Explanation -
Chlamydia trachomatis causes -
Uretheritis,
Pneumonia
Conjunctivitis
Lymphogranuloma venereum
Trachoma.

Explanation: Walking barefooted on soil predisposes to infection. An important public health measure was requiring children to wear shoes to school.

Chlamydia is intracellular so can't be seen under microscope. & has flexible thin wall.

Explanation :
Fungi -
Eukaryotes 
Mitochondria and endoplasmic reticulum present
Sterol present in cell membrane 
Chitin present in cell wall
Sexual and asexual spores are present

Heat sensitive surgical instruments are sterilized by Ethylene oxide gas, Glutaraldehyde solution

The source of transmission is humans with active tuberculosis who release mycobacteria present in sputum.

Most common location of secondary tuberculosis of lung is Apex

Skin can be penetrated by Strongyloides

VDRL is Non-Specific antibody tests for syphilis

S. hematobium is found in urinary tract

• Pseudomonas aeruginosa most commonly causes hospital-acquired infections

Most common types of tertiary disease are gumma (benign granulomatous lesion), cardiovascular syphilis (ascending aorta aneurysm) & symptomatic neurosyphilis (tabes dorsalis and paresis).

Explanation -
Transplacental transmission  :
Treponema pallidum
Listeria monocytogens
Cytomegalovirus 
Parbovirus B19
Rubella virus
Measles virus
HIV
Toxoplasma gondii 

Through birth canal :
Streptococcus agalactiae

The gametocytes of P. falciparum are crescent-shaped (“banana-shaped”), whereas those of the other plasmodia are spherical.

Explanation :
Live bacterial vaccine -
BCG,Live cholera vaccine,Typhoid vaccine
Live viral vaccine -
MMR,Varicella,Influenza,Rota virus,OPV,Small pox, Adeno virus,Yellow fever vaccine.

Shallow and punched out ulcer is found in chancre

The most common cause of “traveler’s diarrhea” is Escherichia coli

Scenario reveals primary syphilis chancre which is painless.

E coli causes meningitis in neonate

Explanation: Gram-negative bacilli (Escherichia coli, Proteus) and Group B streptococci causes meningitis in neonate

Explanation :
Non enveloped DNA virus :

Parbo virus B19
Papilloma virus
Adeno virus

Enveloped DNA virus :
Herpes virus family
Pox virus family
Hepadna virus.

Explanation: A single dose of albendazole (400 mg) is the treatment of choice. Alternatively, mebendazole 100 mg twice daily for 3 days may be used.

Anti HBs is positive in immunized people without infection?

Causes of Bell's palsy :
Idiopathic
Herpes zoster infection
Brainstem infraction
Tumor in the cerebello pontine angle
Acoustic neuroma
Parotid tumor
Fracture of petrous part of temporal bone

duodenale causes microcytic anaemia

Tertian malaria is subdivided into malignant malaria, caused by P. falciparum, and benign malaria, caused by P. vivax and P. ovale.

Explanation: E.coli is the most common cause of UTI

Dog is the definitive host in E. Granulosus

Amoebiasis is caused by E. histolytica

• Infection by M. tuberculosis proceeds in steps, from initial infection of macrophages to a subsequent TH1 response that both contains the bacteria and causes tissue damage

Rabies virus is bullet shaped, enveloped, single-strand RNA virus of negative polarity. The first step in viral replication is synthesis of full-length copies (postive strands) of the viral genome.

Explanation: Humans are infected by eating food contaminated with mature ova. Ascaris larvae hatch in the duodenum, migrate through the lungs, ascend the bronchial tree, are swallowed and mature in the small intestine

Causes of acute pneumonias in the community include H. influenzae and M. catarrhalis (both associated with acute exacerbations of COPD), S. aureus (usually secondary to viral respiratory infections), K. pneumoniae (observed in patients who are chronic alcoholics), P. aeruginosa (seen in persons with cystic fibrosis, in burn victims, and in patients with neutropenia), and L. pneumophila, seen particularly in organ transplant recipients.

Explanation: WBC & nitrite in urine is suggestive of UTI

Explanation: P. falciparum infects all stages of RBC

This fungus can be stuck by rose thorn.

• S. pneumoniae (the pneumococcus) is the most common cause of community-acquired acute pneumonia; the distribution of inflammation is usually lobar.

Quartan malaria is caued by P. Malariae

Explanation: Tularaemia and spores of bacillus used as bioterrorism

Explanation :
Mycobacterium -
Rigid cell wall contain mycolic acid
M.fortuitum is rapid growing
Causes growth primarily in lungs

Western blot is confirmatory for HIV, if it is indeterminate, we will repeat this after one month.

Explanation: Syphilis is caused by T.pallidum

Cellulitis is spreading infection & caused by S. Pyogens. Hyaluronidase is the spreading factor.

Explanation : Listeria causes more significant invasive infection , especially in pregnant women, older adults ( over 55 years ) and the immunocompromised.

• Diagnosis rests on microscopic examination of blood, using both thick and thin Giemsa-stained smears.
• The thick smear is used to screen for the presence of organisms, and the thin smear is used for species identification.

Explanation: Streptococcus pneumoniae or pneumococcus is the most common cause of acute community-acquired pneumonia.

Cyst of E. Histolytica is found in stool

Chagas disease is caused by T. cruzi

Explanation: Ancylostomiasis is caused by Ancylostoma duodenale or Necator americanus

• When the vertebrae are affected, the disease is referred to as Pott disease.

Explanation: Hepatitis (A,B,C,D,E), Cytomegalovirus, Epstein–Barr virus, Herpes simplex and Yellow fever virus causes viral hepatitis.

Normal Flora of vagina maintained by Oestrogen