Biology

Foot-and-mouth disease, a contagious viral disease for cattle, sheep, goats and pigs, resurfaced in Indonesia in May 2022 after the country had been declared free of it for over 30 years. What makes FMD virus so remarkable is its environmental resistance. It can persist on many inanimate objects, such as equipment used with livestock, people’s clothing and shoes, on the tyres of vehicles and in livestock transport. It can also persist in livestock feed and livestock products, such as meat and hides. There is no cure for FMD. Outline a strategy that could prevent the spread of FMD to Australia.

Human papillomavirus (HPV) is a group of viruses that infect the skin and mucous membranes of humans. HPV viruses are classified into different serotypes based on the DNA sequences of their viral genomes. Each HPV type is identified by a specific number (e.g., HPV-16, HPV-18, etc.). HPV types can cause changes in the cells of the cervix, leading to the development of precancerous lesions. If these lesions are left untreated, they may progress to invasive cervical cancer. HPV binds to the surface of epithelial cells and gain entry via endocytosis. Once inside the cell it introduces its viral DNA into the cells nucleus. It uses the hosts cell’s machinery to produce a viral E6 protein. Schematic of HPV infection of a epithelial cell Adapted from Human Papillomavirus and Oropharynx Cancer: Biology, Detection and Clinical Implications

The graph below shows the ten year cumulative incidence rate of cervical precancer by different HPV serotypes. Patiens were tested for HPV at the beginning of the 10 year period.

Analyse the trends shown in the data.

A new vaccine against an infectious disease was developed. The effectiveness of the vaccine in preventing infection in humans was plotted over time in three different age groups.

Which of the following is a valid conclusion that can be drawn from the data in the graph?
A. The vaccine is ineffective after six months.
B. The younger the person the more effective the vaccine.
C. The younger the person, the faster the immunity to infection declines.
D. The vaccine offers more protection to younger people than those over 65.

Malaria is a disease transmitted by a mosquito vector. There has been no effective vaccine developed. Refer to the maps below to answer Question 30.

Discuss possible reasons for the differences in the distribution of malaria and its vector. Include detailed reference to Map 1 and Map 2.

In 2014, during an outbreak of Ebola virus disease (EVD) in West Africa thousands of local people and several healthcare workers died. Infections resulted from human-to- human transmission through contact with broken skin, mucus, bodily fluids, and secretions. Which of the following measures could prevent future outbreaks of EVD?
A. Administration of antibiotics
B. Isolation of infected people
C. Use of education programs
D. Vaccination of infected people

Howard Florey conducted a breakthrough experiment in the development and use of antibiotics. He infected eight mice with Streptococcus bacteria. Four mice were given penicillin and survived while the four untreated mice died. What conclusion could be drawn from the data obtained?
A. The experiment should be repeated with more mice.
B. The use of penicillin causes antibiotic resistance in mice.
C. Penicillin may be used on humans safely to treat bacterial infections.
D. Penicillin may have played a role in the survival of the four treated mice.

Scientists conducted an experiment to investigate the effectiveness of treating water from storage dams with UV radiation.
The experiment was conducted more than three times. The results are shown in the table.
What conclusion may be drawn from the data obtained?
A. The control plates are contaminated.
B. High doses of UV eliminate all pathogens.
C. Exposure to UV inhibits reproduction of bacteria.
D. The presence of bacteria reduces the amount of UV.

Two pig farmers on neighbouring farms noticed that their pigs were suffering from diarrhoea and gradually losing weight. The farmers each adopted a different strategy to deal with this disease, as shown in the table. Outline ONE benefit and ONE limitation of the strategies used on each farm.

Giardiasis is the most common form of non-bacterial diarrhoea of people in Australia. The adult parasite, Giardia lamblia, responsible for the disease, is shown in the figure below. The adult is a single cell. Its ventral side is flattened and has a shallow depression used as a type of sucker. Giardia lives in the upper part of the intestine (duodenum) of an infected person where it rapidly multiplies. To pass from one human to another it encloses itself in a cyst that passes out in the faeces.
Describe ONE procedure that would be suitable for preventing the spread of Giardia and justify its use.

The graph below shows the change in antibody concentration over time after vaccination involving an initial and then second, or booster, dose.
Identify the time at which the primary and secondary vaccinations were given and account for the features of the graph using your knowledge of primary and secondary immune response. Annotate the graph to support your answer.

Rubella is an infectious disease caused by Rubivirus rubella. The disease is frequently mild, with a characteristic rash often appearing two weeks after exposure and lasting for three days. Other symptoms include fever, sore throat and fatigue, with joint pain common in adults. Up to half of infected cases are asymptomatic. Rubella is usually spread from one person to the next through the air via coughs of people who are infected. People are infectious during the week before and after the appearance of the rash. Only humans are infected. Once recovered, people are immune to future infections. In the early 1940s, Australian ophthalmologist Norman Gregg noticed a high incidence of congenital cataracts in babies whose mothers had suffered from rubella during pregnancy. It was then statistically shown that infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). The main defects result almost exclusively from rubella infection occurring in the first 16 weeks of gestation and include deafness due to cochlea malformation, eye and cardiovascular defects and central nervous system damage leading to mental retardation. Rubella is preventable with a single dose of the rubella vaccine being more than 95% effective. When rubella vaccination became feasible around 1971, both the United States and the United Kingdom embarked on vaccination programs. In the United States, the strategy was to vaccinate infants, so that eventually the reservoir in childhood would be abolished. In contrast, the United Kingdom decided on a program of vaccinating adolescent girls. Both strategies were partial successes, in that CRS incidence began to decrease. Figure 1: Number of Rubella and Congenital Rubella Syndrome Cases in the United States 1966-2011

Use the evidence in the graph to justify the statement that the US program was only a partial success in reducing the rate of CRS.

Rubella is an infectious disease caused by Rubivirus rubella. The disease is frequently mild, with a characteristic rash often appearing two weeks after exposure and lasting for three days. Other symptoms include fever, sore throat and fatigue, with joint pain common in adults. Up to half of infected cases are asymptomatic. Rubella is usually spread from one person to the next through the air via coughs of people who are infected. People are infectious during the week before and after the appearance of the rash. Only humans are infected. Once recovered, people are immune to future infections. In the early 1940s, Australian ophthalmologist Norman Gregg noticed a high incidence of congenital cataracts in babies whose mothers had suffered from rubella during pregnancy. It was then statistically shown that infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). The main defects result almost exclusively from rubella infection occurring in the first 16 weeks of gestation and include deafness due to cochlea malformation, eye and cardiovascular defects and central nervous system damage leading to mental retardation. Rubella is preventable with a single dose of the rubella vaccine being more than 95% effective. When rubella vaccination became feasible around 1971, both the United States and the United Kingdom embarked on vaccination programs. In the United States, the strategy was to vaccinate infants, so that eventually the reservoir in childhood would be abolished. In contrast, the United Kingdom decided on a program of vaccinating adolescent girls. Both strategies were partial successes, in that CRS incidence began to decrease. Figure 1: Number of Rubella and Congenital Rubella Syndrome Cases in the United States 1966-2011
Justify a hypothesis as to why the UK program was only a partial success in reducing the rate of CRS.
Hypothesis:………………………………………………………………………………………
Justification:………………………………………………………………………………………

Rubella is an infectious disease caused by Rubivirus rubella. The disease is frequently mild, with a characteristic rash often appearing two weeks after exposure and lasting for three days. Other symptoms include fever, sore throat and fatigue, with joint pain common in adults. Up to half of infected cases are asymptomatic. Rubella is usually spread from one person to the next through the air via coughs of people who are infected. People are infectious during the week before and after the appearance of the rash. Only humans are infected. Once recovered, people are immune to future infections. In the early 1940s, Australian ophthalmologist Norman Gregg noticed a high incidence of congenital cataracts in babies whose mothers had suffered from rubella during pregnancy. It was then statistically shown that infection during early pregnancy may result in a miscarriage or a child born with congenital rubella syndrome (CRS). The main defects result almost exclusively from rubella infection occurring in the first 16 weeks of gestation and include deafness due to cochlea malformation, eye and cardiovascular defects and central nervous system damage leading to mental retardation. Rubella is preventable with a single dose of the rubella vaccine being more than 95% effective. When rubella vaccination became feasible around 1971, both the United States and the United Kingdom embarked on vaccination programs. In the United States, the strategy was to vaccinate infants, so that eventually the reservoir in childhood would be abolished. In contrast, the United Kingdom decided on a program of vaccinating adolescent girls. Both strategies were partial successes, in that CRS incidence began to decrease.

Describe the trends in the incidence of infectious rubella cases.

Citrus canker is a bacterial disease that originates in south-east Asia and affects citrus fruit. What would be the most effective way to prevent the disease from spreading into or across Australia?
A. Monitor citrus trees and fruit continuously.
B. Certify orchards before fruit is transported.
C. Keep citrus trees and fruit entering Australia in quarantine stations until the incubation period has passed.
D. Inspect citrus trees and fruit entering Australia in quarantine stations before transportation across Australia.

Four antiviral drugs have been tested in a culture of human cells for their effectiveness in inhibiting infection from a new virus. The toxicity of the antivirals to human cells was also tested.
The ability of the drugs to inhibit viral entry to the cells (% inhibition) and the proportion of the cells killed by the drugs (% toxicity) were recorded at different doses of each drug and shown in the graphs.
From the results shown, which antiviral drug is the safest and most effective at a dose of 1 µ mol L–1?

Cholera is an acute diarrhoeal infection caused by the bacterium Vibrio cholerae. Humans are infected when they consume food or water that is contaminated with the bacterium.
Outline THREE strategies that could prevent the spread of cholera.

Outline a benefit and a limitation of using pharmaceuticals such as antibiotics to treat infectious disease.

Explain the impact that genetic technologies have had on the management of both infectious and non-infectious diseases.

Post exposure prophylaxis (PEP) is given to patients who have been bitten by a rabid animal. PEP includes an injection of human rabies antibodies (HRIG) as well as injections of a rabies vaccine at 0, 3, 7 and 14 days after exposure to the virus. The following graphs show a generalised response to rabies infection without and with PEP.
Explain how PEP prevents rabies developing after infection with the virus. Support your answer with reference to the information and data provided throughout Question 32.

Two types of bacteria were isolated from a patient’s throat swab and grown in pure culture on separate agar plates. On each plate there were FOUR different antibiotic discs, W, X, Y and Z . The photograph shows the plates seven days later.

Which antibiotic should be used to treat the patient?A. W
B. X
C. Y
D. Z

A group of islands are separated from each other by large stretches of water. Each island has its own policy on quarantine. A nearby country is experiencing an outbreak of an infectious disease in its cattle. An investigation is to be designed to find which of the quarantine policies operating on the islands is the most effective. Which of the following would be a suitable design feature of the investigation?
A. The control is the smallest island.
B. The control is the number of infected cattle.
C. The independent variable is quarantine policy.
D. The independent variable is the number of infected cattle.