Cryptococcal meningitis is a serious fungal infection that affects the membranes surrounding the brain and spinal cord. It is important to defer ART initiation for clients diagnosed with cryptococcal meningitis until 4-6 weeks of antifungal treatment has been completed because starting ART too soon can lead to a condition known as immune reconstitution inflammatory syndrome (IRIS).

IRIS occurs when the immune system begins to recover and responds aggressively to the infection, causing inflammation and potentially worsening symptoms. By waiting until the antifungal treatment has had time to reduce the fungal burden and stabilize the infection, the risk of developing IRIS is minimized.

Therefore, it is crucial to prioritize treating the cryptococcal meningitis first before starting ART in order to ensure the best possible outcome for the client.

This question presents a case of an elderly man with a chronic cough, haemoptysis, night sweats, and a history of smoking and previous tuberculosis treatment. The patient also has evidence of consolidation in the right upper lobe on chest X-ray and positive Aspergillus precipitins.

The most likely diagnosis in this case is aspergilloma. Aspergilloma is a fungus ball that develops in a pre-existing cavity in the lung parenchyma. It is commonly seen in patients with pre-existing cavitary lung diseases such as tuberculosis. Symptoms of aspergilloma may include cough, haemoptysis, and fever. The presence of positive Aspergillus precipitins further supports the diagnosis.

The other options provided in the question are less likely based on the clinical presentation and investigations. Allergic bronchopulmonary aspergillosis typically presents with asthma-like symptoms and eosinophilia. Invasive aspergillosis is a severe infection that occurs in immunocompromised individuals. Reactivated tuberculosis would typically present with symptoms similar to the initial infection. Lung cancer would have a different presentation on imaging and would not be associated with positive Aspergillus precipitins.

Enhanced Adherence Counselling (EAC) plays a crucial role in providing support for patients who are facing challenges with remembering to take their treatment. It is not an optional service for patients interested in complementary medicine, primarily for caregivers, or used only in cases of drug resistance. EAC is not a one-time intervention during initial diagnosis, but rather an ongoing support service for patients struggling with adherence to their ART regimen. By offering personalized care plans and individualized support, EAC aims to improve treatment outcomes by helping patients stay on track with their medication schedule.

Mumps is a viral infection that primarily affects the salivary glands, causing swelling and pain. It is most common in children, but can also affect adults who have not been vaccinated. In this case, the 10-month-old boy was exposed to another child with mumps, which raises concerns about his risk of contracting the infection.

The most appropriate management for this child would be to do nothing now but give the MMR (measles, mumps, rubella) vaccine at the appropriate age. The reason for this is that immunity against mumps takes time to develop after vaccination. By following the recommended vaccination schedule, the child will receive protection against mumps and other diseases included in the MMR vaccine.

The other options, such as assessing mumps serology or giving mumps immunoglobulin, are not necessary in this case. It is important to follow the standard vaccination guidelines to ensure the child’s long-term protection against mumps and other preventable diseases.

The recommended course of action is to order a combination test for HIV p24 antigen and HIV antibody. The patient is exhibiting symptoms of HIV seroconversion and had unprotected intercourse 4 weeks ago. Combination tests are now the standard for HIV diagnosis and screening, with p24 antigen tests typically turning positive between 1 and 4 weeks post-exposure and antibody tests turning positive between 4 weeks and 3 months post-exposure. If a patient at risk tests positive, the diagnosis should be confirmed with a repeat test before starting treatment.

Offering post-exposure prophylaxis is not appropriate in this case, as the patient had unprotected intercourse 3 weeks ago. Two NRTIs and an NNRTI should not be prescribed as treatment, as the patient has not yet tested positive. Ordering only a p24 antigen or antibody test alone is also not recommended, as combination tests are now standard practice.

Understanding HIV Seroconversion and Diagnosis

HIV seroconversion is a process where the body develops antibodies to the HIV virus after being infected. This process is symptomatic in 60-80% of patients and usually presents as a glandular fever type illness. Symptoms may include sore throat, lymphadenopathy, malaise, myalgia, arthralgia, diarrhea, maculopapular rash, mouth ulcers, and rarely meningoencephalitis. The severity of symptoms is associated with a poorer long-term prognosis and typically occurs 3-12 weeks after infection.

Diagnosing HIV involves testing for HIV antibodies, which may not be present in early infection. However, most people develop antibodies to HIV at 4-6 weeks, and 99% do so by 3 months. The diagnosis usually consists of both a screening ELISA test and a confirmatory Western Blot Assay. Additionally, a p24 antigen test may be used to detect a viral core protein that appears early in the blood as the viral RNA levels rise. Combination tests that test for both HIV p24 antigen and HIV antibody are now standard for the diagnosis and screening of HIV. If the combined test is positive, it should be repeated to confirm the diagnosis. Testing for HIV in asymptomatic patients should be done at 4 weeks after possible exposure, and after an initial negative result, a repeat test should be offered at 12 weeks.

Endogenous transmission refers to the spread of infection by organisms that are normally present in the body but have become pathogenic due to certain conditions. This type of transmission occurs when the body’s own flora, which are usually harmless, gain access to a different part of the body where they can cause infection.

In contrast, exogenous transmission involves the introduction of pathogens from external sources. For example, inhalation of secretions containing a pathogen, direct person-to-person spread, transfer due to poor hygiene and contaminated food, and transfer from pets or other animals are all examples of exogenous infections.

Therefore, the statement Commensal flora that gain access to an inappropriate area best describes endogenous transmission, as it involves the activation of normally harmless flora within the body.

Orchitis typically affects post-pubertal males and usually occurs 5-7 days after infection. It is important to note that the relief of pain when the testis is elevated, known as a positive Prehn’s sign, is not present in cases of testicular torsion.

Epididymo-orchitis is a condition where the epididymis and/or testes become infected, leading to pain and swelling. It is commonly caused by infections spreading from the genital tract or bladder, with Chlamydia trachomatis and Neisseria gonorrhoeae being the usual culprits in sexually active younger adults, while E. coli is more commonly seen in older adults with a low-risk sexual history. Symptoms include unilateral testicular pain and swelling, with urethral discharge sometimes present. Testicular torsion, which can cause ischaemia of the testicle, is an important differential diagnosis and needs to be excluded urgently, especially in younger patients with severe pain and an acute onset.

Investigations are guided by the patient’s age, with sexually transmitted infections being assessed in younger adults and a mid-stream urine (MSU) being sent for microscopy and culture in older adults with a low-risk sexual history. Management guidelines from the British Association for Sexual Health and HIV (BASHH) recommend ceftriaxone 500 mg intramuscularly as a single dose, plus doxycycline 100 mg orally twice daily for 10-14 days if the organism causing the infection is unknown. Further investigations are recommended after treatment to rule out any underlying structural abnormalities.

It is important for non-pregnant women of childbearing potential to receive education on good nutrition and lifestyle in order to maintain their overall health and prepare their bodies for a potential pregnancy. Screening for TB and STIs is crucial to ensure that any infections are detected and treated promptly, reducing the risk of complications during pregnancy. Encouraging these women to attend antenatal clinics regularly can help monitor their reproductive health and address any concerns or issues that may arise. Additionally, offering HIV testing to both the woman and her partner is important for preventing the transmission of the virus to the unborn child and ensuring appropriate care and support for the family. Therefore, all of the above options are recommended for the care of non-pregnant women of childbearing potential at home.

Antibiotic prophylaxis is recommended for certain medical procedures to prevent infective endocarditis in patients with certain heart conditions. However, recent guidelines from the National Institute for Health and Care Excellence (NICE) have determined that patients with isolated atrial septal defects do not require antibiotic prophylaxis for dental procedures. This is because the risk of developing infective endocarditis in these patients is considered to be very low.

The other procedures listed, such as cholecystectomy, emergency sigmoid colectomy, splenectomy, and total hip replacement, may still require antibiotic prophylaxis in certain cases depending on the patient’s individual medical history and risk factors for infective endocarditis.

Hepatorenal syndrome is a serious complication of liver cirrhosis that can lead to kidney failure. In patients with spontaneous bacterial peritonitis, the risk of developing hepatorenal syndrome is increased. In this case, the best treatment option to prevent the patient from developing hepatorenal syndrome is intravenous albumin administration.

Albumin has been shown in randomized controlled trials to have a positive effect on circulatory systems, which can help prevent the development of hepatorenal syndrome. Central venous pressure monitoring can help assess the patient’s fluid status, but in this case, the patient does not have symptoms of hypovolaemia. Intravenous dopamine infusion is not indicated for the prevention of hepatorenal syndrome.

Regular lactulose use is primarily used for the prevention of hepatic encephalopathy, which is not relevant in preventing hepatorenal syndrome. Neomycin, while sometimes used for hepatic encephalopathy, is associated with nephrotoxicity and ototoxicity and is not recommended for preventing hepatorenal syndrome.

Therefore, in this case, the best treatment option to prevent the patient from developing hepatorenal syndrome is intravenous albumin administration.

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. The primary treatment for syphilis is penicillin, as it is highly effective in killing the bacteria. However, some patients may have a penicillin allergy, which can complicate treatment.

In cases where patients have a penicillin allergy, azithromycin is recommended as an alternative treatment for syphilis. Azithromycin is a macrolide antibiotic that is effective against a wide range of bacteria, including Treponema pallidum. It is typically given as a single dose or a short course of treatment, making it a convenient option for patients who cannot take penicillin.

Other antibiotics, such as doxycycline, clindamycin, and vancomycin, are not typically used as first-line treatments for syphilis. Ciprofloxacin is not effective against Treponema pallidum and should not be used to treat syphilis.

In conclusion, azithromycin is the recommended antibiotic for treating syphilis in patients with a penicillin allergy. It is important for healthcare providers to be aware of alternative treatment options for patients with allergies to ensure effective management of the infection.

Dolutegravir (DTG) is the ART drug associated with an increased risk of neural tube defects (NTDs) if used during the periconception period. Neural tube defects are birth defects that affect the brain, spine, or spinal cord of a developing fetus. Studies have shown that women who were taking DTG at the time of conception or early pregnancy had a higher risk of having a child with NTDs compared to women taking other ART drugs.

This increased risk has led to recommendations for careful counseling and consideration of alternative regimens for women of childbearing potential who are taking DTG. It is important for healthcare providers to discuss the potential risks and benefits of DTG with their patients and to consider switching to a different ART drug if pregnancy is planned or possible. This can help to minimize the risk of NTDs and ensure the health and safety of both the mother and the developing fetus.

Lipodystrophy is a common side effect of certain antiretroviral drugs used to treat HIV, such as Efavirenz (EFV). Lipodystrophy is characterized by changes in body fat distribution, including fat loss in the face, arms, legs, and buttocks, and fat accumulation in the abdomen, back of the neck, and breasts. This can lead to metabolic abnormalities such as insulin resistance, dyslipidemia, and increased risk of cardiovascular disease.

Among the options provided, Efavirenz (EFV) is the drug commonly associated with lipodystrophy. Ritonavir (RTV) is more commonly associated with metabolic abnormalities such as dyslipidemia and insulin resistance. Nevirapine (NVP) is not typically associated with lipodystrophy, but can cause liver toxicity. Tenofovir disoproxil fumarate (TDF) is known to cause renal toxicity and bone loss, but not specifically lipodystrophy. Abacavir (ABC) is associated with hypersensitivity reactions, but not typically lipodystrophy.

It is important for healthcare providers to closely monitor patients on EFV for signs of lipodystrophy and metabolic abnormalities, and to intervene as needed to mitigate these adverse effects. This may include switching to a different antiretroviral drug or implementing lifestyle changes to manage metabolic abnormalities.

Antenatal care is essential for ensuring the health and well-being of both the mother and the unborn child during pregnancy. The primary objectives of antenatal care typically include identifying and managing various health conditions that can affect the pregnancy and the health of the mother and baby.

In the options provided, identifying HIV infection and achieving viral suppression, identifying and treating syphilis and other infections, preventing transmission of hepatitis B virus (HBV) and other infections, and providing routine antenatal care according to guidelines are all primary objectives of antenatal care. These objectives focus on preventing and managing infectious diseases that can impact the health of the mother and baby during pregnancy.

However, screening for tuberculosis and other opportunistic infections is not typically considered a primary objective of antenatal care. While it is important to screen for and manage these infections, they are not directly related to the health of the mother and baby during pregnancy. Antenatal care primarily focuses on ensuring a healthy pregnancy and addressing any potential risks or complications that may arise.

Any blood test used to detect HIV infection must have a high degree of sensitivity (the probability that the test will be positive if the patient is infected) and specificity (the probability that the test will be negative if the patient is uninfected). Unfortunately, no antibody test is ever 100 % sensitive and specific. Therefore, if available, all positive test results should be confirmed by retesting, preferably by a different test method. HIV antibody tests usually become positive within 3 months of the individual being infected with the virus (the window period). In some individuals, the test may not be positive until 6 months or longer (considered unusual). In some countries, home testing kits are available. These tests are not very reliable, and support such as pre and post test counselling is not available.

Abandoned infants with unknown HIV exposure are managed as higher-risk, HIV-exposed infants because they are considered to be at increased risk of HIV infection due to their unknown exposure status. This approach ensures that these infants receive appropriate care and treatment in a timely manner to prevent HIV transmission and improve their health outcomes.

Immediate ART initiation based on assumptions is not recommended as it is important to confirm the infant’s HIV status before starting treatment. Waiting for parental consent before any procedure may delay necessary interventions for the infant’s health. Providing only supportive care without specific HIV-focused interventions may put the infant at risk of HIV transmission if they are indeed infected.

Therefore, treating abandoned infants with unknown HIV exposure as higher-risk, HIV-exposed infants allows for prompt initiation of ART and appropriate follow-up testing to confirm their HIV status and provide necessary care. This approach aligns with the guidelines for managing infants with potential HIV exposure and ensures the best possible outcomes for these vulnerable infants.

Hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, that is the first serologic marker to appear in a new acute infection.It can be detected as early as 1 week and as late as 9 weeks. It can be detected in high levels in serum during acute or chronic hepatitis B virus infection. The presence of HBsAg indicates that the person is infectious. The body normally produces antibodies to HBsAg as part of the normal immune response to infection. HBsAg is the antigen used to make hepatitis B vaccine.
Hepatitis B surface antibody (anti-HBs) indicates recovery and immunity from the hepatitis B virus infection. Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B.
Total hepatitis B core antibody (anti-HBc): Appears at the onset of symptoms in acute hepatitis B and persists for life. The presence of anti-HBc indicates previous or ongoing infection with hepatitis B virus in an undefined time frame. It is not present following hepatitis B vaccination.
IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates recent infection with hepatitis B virus (<6 months). Its presence indicates acute infection.
The following table summarises the presence of hepatitis B markers according to each situation:
Susceptible to infection:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = Negative

Immune due to natural infection:
HBsAg = Negative
Anti-HBc = Positive
Anti-HBs = Positive

Immune due to vaccination:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = Positive

Acute infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Positive

Chronic infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Negative

Herpes Simplex Virus (HSV) infection in neonates can be a serious and life-threatening condition, especially when it presents as disseminated infection. In this case, the infant was treated with antivirals upon clinical suspicion, which is crucial in improving outcomes.

The case fatality rate of infants who develop disseminated HSV despite treatment is 0.3, or 30%. This means that even with treatment, there is still a significant risk of mortality for these infants. However, without treatment, the case fatality rate for disseminated HSV infection is much higher at 85%.

It is important for healthcare providers to be vigilant for signs of HSV infection in neonates, especially in cases where the mother has a history of HSV or had a recent outbreak before delivery. Early recognition and prompt treatment with antivirals can greatly improve the chances of survival for these infants.

Oral Candidiasis and its Association with Immune System Defects

Oral candidiasis, a fungal infection in the mouth, is a concerning condition in young healthy individuals as it may indicate an underlying defect in the immune system. Further investigation is necessary to identify the root cause of the infection. In London, men who have sex with men have a high prevalence of HIV, which is a likely diagnosis in such cases. HIV weakens the immune system, making individuals more susceptible to infections and other health complications.

Apart from HIV, other immune system defects may also lead to oral candidiasis. Recurrent attacks of shingles in a young person may also indicate a weakened immune system. Additionally, HIV infection is a predisposing factor for deep vein thrombosis (DVT), a condition where blood clots form in the veins deep within the body. Therefore, it is crucial to investigate the underlying cause of oral candidiasis and other related conditions to ensure timely diagnosis and appropriate treatment.

Overall, oral candidiasis is a red flag for immune system defects, and healthcare professionals should be vigilant in identifying and addressing the root cause of the infection.

The primary purpose of the Nutritional Assessment during the baseline clinical evaluation is to evaluate the nutritional status of the individual. This assessment helps healthcare providers identify any recent weight loss, which can be a sign of an active opportunistic infection. By identifying weight loss early on, healthcare providers can intervene and provide appropriate treatment to address the underlying infection and prevent further complications. This assessment is crucial in the overall management and care of individuals living with HIV/AIDS, as proper nutrition plays a key role in maintaining overall health and immune function.

The clinical picture of the patient together with paraclinical investigations (spirometry) suggest COPD.

The BCG vaccine is a live vaccine that is used to protect against tuberculosis. In patients with asplenia, all vaccines, whether live or inactivated, are generally safe to administer. This is because individuals without a spleen have a weakened immune system and are at higher risk for infections, so vaccination is important for their protection.

Anaphylaxis following any vaccination is a contraindication to receiving that vaccine again. This is because anaphylaxis is a severe allergic reaction that can be life-threatening, so it is important to avoid any triggers that may cause it.

Pregnancy is a contraindication for live vaccines, including the BCG vaccine. This is because live vaccines have the potential to harm the developing fetus, so they are generally not recommended during pregnancy.

HIV infection, whether asymptomatic or symptomatic, is also a contraindication for live vaccines. This is because individuals with HIV have a weakened immune system and may not be able to mount an effective response to the vaccine, putting them at risk for complications.

In summary, the BCG vaccine would be safe to administer to a patient who is asplenic, but not to a patient who has had anaphylaxis following their first BCG vaccination, is pregnant, or is HIV positive.

The essential part of the baseline assessment for an infant diagnosed with HIV is a clinical review and blood tests, including a confirmatory HIV PCR. This is important to confirm the diagnosis of HIV in the infant and to determine the viral load and CD4 count, which are important indicators of the progression of the disease and the need for treatment. Additionally, an HIV drug resistance test may be necessary, especially if the mother is failing treatment on a specific regimen. This comprehensive assessment helps healthcare providers to develop an appropriate treatment plan and monitor the infant’s health and response to treatment over time. Other assessments such as dental examination, hearing test, eye examination, and skin sensitivity test may also be important for the overall health and well-being of the infant, but the clinical review and blood tests are crucial for managing HIV in the infant.

The first viral load (VL) test after initiating antiretroviral therapy (ART) is crucial in monitoring the effectiveness of the treatment and ensuring viral suppression. By conducting the VL test after 3 dispensing cycles, healthcare providers can assess how well the ART regimen is working and if the patient is achieving the desired viral suppression levels.

Testing after 3 dispensing cycles allows for enough time for the medication to take effect and for the patient’s viral load to stabilize. This timing also aligns with the typical follow-up schedule for patients starting ART, making it a convenient and practical time to conduct the test.

Early detection of any issues affecting viral suppression is key to optimizing treatment outcomes and preventing the development of drug resistance. By monitoring the viral load early on in the treatment process, healthcare providers can make necessary adjustments to the ART regimen or provide additional support to help the patient achieve and maintain viral suppression.

Overall, conducting the first VL test after 3 dispensing cycles is a recommended practice in the 2023 ART Clinical Guidelines to ensure effective monitoring of treatment progress and improve outcomes for individuals living with HIV.

Women of childbearing potential with abnormal renal function are at a higher risk for complications during pregnancy, as well as potential adverse effects from certain antiretroviral medications. Tenofovir disoproxil fumarate (TDF) is known to cause renal toxicity in some patients, so it is contraindicated for use in individuals with abnormal renal function.

The recommended regimen for women with abnormal renal function includes zidovudine (AZT), lamivudine (3TC), and dolutegravir (DTG) once daily. AZT and 3TC are both nucleoside reverse transcriptase inhibitors that are safe to use in patients with renal impairment. DTG is an integrase inhibitor that has shown to be effective and well-tolerated in individuals with renal dysfunction.

Therefore, the regimen of AZT, 3TC, and DTG once daily is the most appropriate choice for women of childbearing potential with abnormal renal function, as it provides effective HIV treatment while minimizing the risk of renal toxicity.

Hepatitis A is primarily transmitted through the faecal-oral route, which means that the virus is passed from one person to another through contaminated food, water, or objects. When an infected person does not properly wash their hands after using the bathroom, the virus can be spread to surfaces or food that others come into contact with. When these contaminated items are then ingested by another person, they can become infected with the virus.

Sexual transmission of Hepatitis A is possible, but it is not as common as the faecal-oral route. The virus can be spread through sexual contact with an infected person, particularly through oral-anal contact.

Parenteral transmission refers to the transmission of the virus through blood or bodily fluids, such as sharing needles or other drug paraphernalia. However, Hepatitis A is not typically spread through these routes.

Vector-borne transmission refers to the spread of a virus through insects or other animals. Hepatitis A is not transmitted through vectors.

Direct skin contact is not a common route of transmission for Hepatitis A. The virus is primarily spread through ingestion of contaminated food or water.

In conclusion, the correct answer is the faecal-oral route, as Hepatitis A is most commonly transmitted through contaminated food, water, or objects that have been contaminated with the virus.

The question presents a 16-year-old female with HIV who is experiencing blurring of vision and blind spots in her field of vision. Given her low CD4 count of 45 cells/mL, the most likely complication that has occurred is cytomegalovirus (CMV) retinitis. This condition is a common ocular manifestation of HIV infection, especially in patients with severely compromised immune systems. CMV retinitis typically occurs when the CD4 count falls below 50/μL, making this patient’s CD4 count of 45 cells/mL a significant risk factor.

CMV retinitis is characterized by inflammation of the retina, leading to symptoms such as blurring of vision and blind spots. The treatment for CMV retinitis involves systemic intravenous administration of antiviral medications such as Ganciclovir or Foscarnet. These medications help to control the viral replication and prevent further damage to the retina. Maintenance treatment with oral Ganciclovir is often necessary to prevent recurrence of the infection.

In conclusion, the most likely complication that has occurred in this patient with HIV, resulting in her ocular damage, is CMV retinitis. It is important for healthcare providers to be aware of this potential complication in HIV-infected patients with low CD4 counts, as early detection and treatment are crucial in preventing permanent vision loss.

Individuals with HIV who also have schizophrenia require careful consideration when selecting psychotropic medications due to potential drug interactions and side effects. In this case, the most suitable treatment option for psychosis in individuals with HIV is risperidone, an atypical antipsychotic with a strong evidence base. Risperidone has been shown to effectively treat psychosis while minimizing the risk of adverse effects and drug interactions in individuals with HIV.

Other atypical antipsychotics such as quetiapine, aripiprazole, and olanzapine are also viable options for treating psychosis in individuals with HIV. However, clozapine may be considered as a last resort due to the need for close monitoring and potential risks associated with its use in this population.

It is important for the physician overseeing the medical care of the 50-year-old man with schizophrenia and HIV to carefully consider the potential benefits and risks of each treatment option before making a decision. Close monitoring and regular follow-up appointments are essential to ensure the safety and effectiveness of the chosen psychotropic medication in managing psychosis in individuals with HIV.

Highly active antiretroviral therapy (HAART) is a combination of medications used to treat HIV that has been highly effective in reducing the viral load in individuals who are HIV positive. This has led to significant improvements in their immune function and overall health.

Toxoplasmosis is an opportunistic infection caused by the parasite Toxoplasma gondii that can affect individuals with weakened immune systems, such as those with HIV. With the use of HAART, the immune system is strengthened and able to better fight off infections, leading to a decrease in the occurrence of toxoplasmosis in individuals who are HIV positive.

On the other hand, conditions like PML (progressive multifocal leukoencephalopathy) and lymphoma have shown a slight increase in incidence in individuals who are HIV positive and on HAART. This may be due to the fact that while HAART is effective in controlling HIV and preventing opportunistic infections like toxoplasmosis, it may not be as effective in preventing other conditions like PML and lymphoma.

In conclusion, the use of HAART has been successful in eliminating new cases of toxoplasmosis in individuals who are HIV positive, but there may still be challenges in preventing other conditions that can arise in this population.

Hepatitis B surface antigen (HBsAg) is a protein on the surface of the hepatitis B virus, that is the first serologic marker to appear in a new acute infection.It can be detected as early as 1 week and as late as 9 weeks. It can be detected in high levels in serum during acute or chronic hepatitis B virus infection. The presence of HBsAg indicates that the person is infectious. The body normally produces antibodies to HBsAg as part of the normal immune response to infection. HBsAg is the antigen used to make hepatitis B vaccine.
Hepatitis B surface antibody (anti-HBs) indicates recovery and immunity from the hepatitis B virus infection. Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B.
Total hepatitis B core antibody (anti-HBc): Appears at the onset of symptoms in acute hepatitis B and persists for life. The presence of anti-HBc indicates previous or ongoing infection with hepatitis B virus in an undefined time frame. It is not present following hepatitis B vaccination.
IgM antibody to hepatitis B core antigen (IgM anti-HBc) indicates recent infection with hepatitis B virus (<6 months). Its presence indicates acute infection.
The following table summarises the presence of hepatitis B markers according to each situation:
Susceptible to infection:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = Negative

Immune due to natural infection:
HBsAg = Negative
Anti-HBc = Positive
Anti-HBs = Positive

Immune due to vaccination:
HBsAg = Negative
Anti-HBc = Negative
Anti-HBs = Positive

Acute infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Positive

Chronic infection:
HBsAg = Positive
Anti-HBc = Positive
Anti-HBs = Negative
IgM anti-HBc = Negative