Nokea
Dengue virus is member of a family called
- A. Hepadnaviridae
- B. Parvoviridae
- C. Flaviviridae
- D. Picornaviridae
Correct Answer: C
Rationale: The correct answer is C: Flaviviridae. Dengue virus belongs to the Flaviviridae family because it is a flavivirus. Flaviviruses are a group of RNA viruses known to cause diseases in humans, such as dengue fever, Zika virus, and yellow fever. This family is characterized by its single-stranded, positive-sense RNA genome and enveloped virion structure. Hepadnaviridae (choice A), Parvoviridae (choice B), and Picornaviridae (choice D) are all different families of viruses that do not include the dengue virus. Hepadnaviridae includes hepatitis B virus, Parvoviridae includes parvoviruses, and Picornaviridae includes enteroviruses like poliovirus.
You may also like to solve these questions
The virulence factors of bacteria include:
- A. size, adhesion, resistance, and mutation
- B. colonization, invasion, toxins, and adhesion
- C. toxins, evasion of body defenses, motility, and size
- D. colonization, chemotaxis, fermentation, and toxins
Correct Answer: B
Rationale: Rationale: The correct answer is B because virulence factors of bacteria are characteristics that enable them to cause disease. Colonization allows bacteria to establish and multiply in the host. Invasion refers to the ability to penetrate host tissues. Toxins are substances produced by bacteria that harm the host. Adhesion is crucial for bacteria to attach to host cells.
A: Size and mutation are not typical virulence factors. Resistance is not directly related to causing disease.
C: While toxins and evasion of body defenses are correct, motility and size are not universally considered virulence factors.
D: Chemotaxis and fermentation are not primary virulence factors, unlike colonization and toxins.
Which of the following is commonly referred to as a pinworm?
- A. protozoans
- B. algae
- C. helminths
- D. fungi
Correct Answer: A
Rationale: The correct answer is A: protozoans. Pinworms are commonly referred to as Enterobius vermicularis, which are parasitic worms belonging to the phylum Nematoda. Protozoans are single-celled organisms, and pinworms are multicellular worms. Algae are photosynthetic organisms, helminths are parasitic worms (which pinworms fall under), and fungi are eukaryotic organisms that include molds and yeasts. Therefore, protozoans are the correct choice for organisms commonly referred to as pinworms.
Which are the epidemic typhus vectors:
- A. Head lice
- B. Body lice
- C. Fleas
- D. Ticks
Correct Answer: A
Rationale: The correct answer is A: Head lice. Epidemic typhus is transmitted by the body louse, Pediculus humanus humanus, which is different from the head louse, Pediculus humanus capitis. Head lice are not known to transmit epidemic typhus. Body lice are the primary vectors for transmitting epidemic typhus. Fleas are vectors for other diseases such as plague, not epidemic typhus. Ticks are vectors for various diseases but not for epidemic typhus. Therefore, the correct vector for epidemic typhus transmission is body lice, making choice A the correct answer.
A source of hospital-acquired infection could be:
- A. New patients in incubation period
- B. Medical staff
- C. Medical instruments
- D. All are correct
Correct Answer: D
Rationale: The correct answer is D because all the choices can contribute to hospital-acquired infections. New patients in the incubation period can spread infections, medical staff can inadvertently transmit infections, and contaminated medical instruments can also be a source of infections. Therefore, it is important to consider all these factors to prevent and control the spread of infections in a hospital setting.
A wound culture grew Gram-negative rods that were oxidase-positive and lactose non-fermenters. What is the most likely microorganism?
- A. Pseudomonas aeruginosa
- B. Escherichia coli
- C. Salmonella typhi
- D. Shigella dysenteriae
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. P. aeruginosa is a Gram-negative rod that is oxidase-positive and lactose non-fermenting. The positive oxidase test indicates the presence of cytochrome c oxidase, a characteristic of P. aerugin. E. coli is lactose fermenting. Salmonella and Shigella are also Gram-negative rods, but they are lactose fermenters, unlike the lactose non-fermenting P. aeruginosa.