What role do birds play in the transmission of the West Nile virus? What insect is the vector? How is hepatitis B transmitted, and which occupational group is at greatest risk of contracting this infection? How do forms A, C, D, and E compare with hepatitis B? How is HIV transmitted? How are HIV/AIDS currently treated, and how effective is the treatment? In what areas of the world does the HIV/AIDS epidemic seem virtually unchecked? In terms of STD prevention, how can sexual practices be made safer? Why are women more often asymptomatic for STDs than men? Solution What role do birds play in the transmission of the west nile virus ?which insect is the vector? Birds are the reservoir hosts of WNV. the virus is highly pathogenic for bird. Members of the crow family (Corvidae) are particularly susceptible, but virus has been detected in dead and dying birds. Birds can be infected by a variety of routes other than mosquito bites, and different species may have different potential for maintaining the transmission cycle. Mosquito is the vector . How is Hepatitis B Transmitted? and which occupational group is at higher risk?how do other forms compare with hepatitis b? Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease.The virus is transmitted through contact with the blood or other body fluids of an infected person.Hepatitis B is an important occupational hazard for health workers. There are 5 main hepatitis viruses, referred to as types A, B, C, D and E. These 5 types are of greatest concern because of the burden of illness and death they cause and the potential for outbreaks and epidemic spread. In particular, types B and C lead to chronic disease in hundreds of millions of people and, together, are the most common cause of liver cirrhosis and cancer. Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids. Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact. How is HIV transmitted? how HIV/AIDS currently treated? and how effective is the treatment? in what areas of the world does the HIV/AIDS epidemic seem virtually unchecked? In terms of STD prevention, how can sexual practices be made safer? Why are women more often asymptomatic for STDs than men ? Women are vulnerable to STDs for social and economic reasons. Compared to men, women generally have low status, education, income and power. Social and economic dependency may limit a woman’s ability to refuse unsafe sex or negotiate safer sex. She may also find it difficult to obtain information about disease prevention, or to seek and receive health care. Women striving to survive economically also may be d.

1. What role do birds play in the transmission of the West Nile virus? What insect is the vector?
How is hepatitis B transmitted, and which occupational group is at greatest risk of contracting
this infection? How do forms A, C, D, and E compare with hepatitis B? How is HIV
transmitted? How are HIV/AIDS currently treated, and how effective is the treatment? In what
areas of the world does the HIV/AIDS epidemic seem virtually unchecked? In terms of STD
prevention, how can sexual practices be made safer? Why are women more often asymptomatic
for STDs than men?
Solution
What role do birds play in the transmission of the west nile virus ?which insect is the vector?
Birds are the reservoir hosts of WNV. the virus is highly pathogenic for bird. Members of the
crow family (Corvidae) are particularly susceptible, but virus has been detected in dead and
dying birds. Birds can be infected by a variety of routes other than mosquito bites, and different
species may have different potential for maintaining the transmission cycle. Mosquito is the
vector .
How is Hepatitis B Transmitted? and which occupational group is at higher risk?how do other
forms compare with hepatitis b?
Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic
disease.The virus is transmitted through contact with the blood or other body fluids of an
infected person.Hepatitis B is an important occupational hazard for health workers.
There are 5 main hepatitis viruses, referred to as types A, B, C, D and E. These 5 types are of
greatest concern because of the burden of illness and death they cause and the potential for
outbreaks and epidemic spread. In particular, types B and C lead to chronic disease in hundreds
of millions of people and, together, are the most common cause of liver cirrhosis and cancer.
Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B,
C and D usually occur as a result of parenteral contact with infected body fluids. Common
modes of transmission for these viruses include receipt of contaminated blood or blood products,
invasive medical procedures using contaminated equipment and for hepatitis B transmission
from mother to baby at birth, from family member to child, and also by sexual contact.
How is HIV transmitted? how HIV/AIDS currently treated? and how effective is the treatment?
in what areas of the world does the HIV/AIDS epidemic seem virtually unchecked? In terms of
STD prevention, how can sexual practices be made safer?
Why are women more often asymptomatic for STDs than men ?
Women are vulnerable to STDs for social and economic reasons. Compared to men, women
generally have low status, education, income and power. Social and economic dependency may

2. limit a woman’s ability to refuse unsafe sex or negotiate safer sex. She may also find it difficult
to obtain information about disease prevention, or to seek and receive health care. Women
striving to survive economically also may be drawn into the sex industry, where STD
transmission is common.
Women are also biologically more vulnerable to STDs than are men. Women are more
susceptible to STDs during sexual intercourse because the vaginal surface is larger and more
vulnerable to sexual secretions than the primarily skin-covered penis. Also, the volume of
potentially infected male ejaculate deposited in a woman’s vagina during intercourse is larger
than the potentially infected cervical and vaginal secretions to which men are exposed.