Common fungal and parasitic infections

Upon completion of this module, you will be able to approach common fungal and parasitic infections encountered in Kenyan clinical practice. Remember to always consult the Kenya MoH guidelines and your hospital formulary for specific drug dosages and local management protocols.

Definition

Fungal infections (mycoses) are diseases caused by pathogenic fungi. Parasitic infections are caused by organisms that live on or in a host organism and derive nourishment at the host's expense.

Anatomy and physiology you need

Understanding the relevant anatomy and physiology is crucial for identifying the site of infection and its impact. This includes:

• Skin and its appendages: Stratum corneum, hair follicles, nails, sweat glands. Fungi and ectoparasites commonly affect these structures.
• Gastrointestinal tract: Mucosa of the oesophagus, stomach, small and large intestines. Key for intestinal parasites and some systemic fungal infections.
• Respiratory tract: Nasal passages, pharynx, larynx, trachea, bronchi, alveoli. Important for airborne fungal spores and some parasites.
• Urinary tract: Kidneys, ureters, bladder, urethra. Susceptible to opportunistic fungal infections.
• Central Nervous System: Meninges, brain parenchyma. Can be affected by specific fungi and parasites.
• Blood and Lymphatic system: Red blood cells, white blood cells, lymph nodes. Crucial for vector-borne parasitic diseases like malaria and filariasis.
• Liver and Spleen: Involved in the lifecycle and immune response to many parasites.

Causes and risk factors

In Kenya, common fungal and parasitic infections are influenced by several factors:

Fungal Infections:

• Opportunistic Fungi: Candida species, Aspergillus species, Cryptococcus neoformans.
  • Risk Factors:
    • HIV/AIDS: Profound immunosuppression significantly increases risk.
    • Tuberculosis (TB): Co-infection, particularly with disseminated TB, can predispose to fungal infections.
    • Malignancy: Haematological malignancies and solid tumours.
    • Immunosuppressive Therapy: Steroids, chemotherapy, organ transplantation.
    • Diabetes Mellitus: Impaired immune function and altered tissue environment.
    • Prolonged Antibiotic Use: Disrupts normal flora, allowing fungal overgrowth.
    • Indwelling Catheters: Central venous catheters, urinary catheters.
• Dermatophytes: Trichophyton, Microsporum, Epidermophyton species.
  • Risk Factors:
    • Warm, humid climate: Promotes fungal growth.
    • Poor hygiene: Close contact with infected individuals or contaminated surfaces.
    • Trauma to skin/nails: Creates entry points.
    • Immunocompromise: Can lead to more extensive or invasive disease.
• Malassezia furfur:
  • Risk Factors:
    • Seborrhoeic skin: Oily skin.
    • Warm, humid conditions.
    • Immunosuppression.

Parasitic Infections:

• Protozoa:
  • ***Plasmodium* species (Malaria):**
    • Risk Factors:
      • Endemic areas: High mosquito vector density.
      • Lack of insecticide-treated nets (ITNs) or indoor residual spraying (IRS).
      • Pregnancy: Increased susceptibility and severity.
      • HIV/AIDS: Can increase malaria risk and severity.
      • Splenectomy: Impaired parasite clearance.
  • ***Entamoeba histolytica* (Amoebiasis):**
    • Risk Factors:
      • Contaminated food and water: Poor sanitation and hygiene.
      • Oral-anal sexual contact.
  • ***Giardia lamblia*:**
    • Risk Factors:
      • Contaminated food and water: Poor sanitation.
      • Close contact in crowded settings (e.g., day-care centres).
  • ***Cryptosporidium* species:**
    • Risk Factors:
      • Contaminated water.
      • Immunocompromise (especially HIV/AIDS).
• Helminths (Worms):
  • **Intestinal Nematodes (e.g., Ascaris lumbricoides, Hookworm, Trichuris trichiura):**
    • Risk Factors:
      • Poor sanitation and hygiene: Fecal-oral transmission.
      • Walking barefoot: Hookworm.
      • Consumption of contaminated raw vegetables.
  • **Schistosomes (Schistosoma mansoni):**
    • Risk Factors:
      • Contact with freshwater containing infected snails: Agricultural work, recreation.
      • Poor sanitation: Contaminated water sources.
  • **Filariasis (e.g., Wuchereria bancrofti):**
    • Risk Factors:
      • Mosquito bites: Vector-borne transmission in endemic areas.
  • Taenia species (Tapeworms):
    • Risk Factors:
      • Consumption of undercooked meat (beef/pork).
  • **Cestodes (e.g., Echinococcus granulosus):**
    • Risk Factors:
      • Contact with infected dogs: Handling dog feces, contaminated food/water.
• Ectoparasites:
  • **Lice (Pediculus humanus capitis, P. h. corporis, Pthirus pubis):**
    • Risk Factors:
      • Close personal contact.
      • Overcrowding.
  • **Scabies mites (Sarcoptes scabiei):**
    • Risk Factors:
      • Close personal contact.
      • Overcrowding and poor hygiene.
      • Immunocompromise: Crusted scabies.

Other Tropical Causes:

• Rheumatic diseases: Can be associated with increased susceptibility to certain infections due to underlying immune dysregulation or treatment.
• Sickle Cell Disease: Impaired splenic function predisposes to encapsulated organisms and certain fungal infections like Salmonella and Aspergillus.

Pathophysiology

Fungal Infections (General):

Fungal spores are ubiquitous. In immunocompetent individuals, the immune system (especially neutrophils and macrophages) effectively controls fungal growth. Immunosuppression $\rightarrow$ Impaired host defences $\rightarrow$ Fungal spore germination and proliferation $\rightarrow$ Tissue invasion $\rightarrow$ Inflammation and organ damage.

Parasitic Infections (General):

Parasites have diverse life cycles and mechanisms of pathogenesis.

• Protozoa (e.g., Malaria):

Sporozoites (from mosquito bite) $\rightarrow$ Liver (replication) $\rightarrow$ Merozoites released into blood $\rightarrow$ Infect red blood cells $\rightarrow$ Erythrocytic cycle (causing haemolysis, fever, anaemia) $\rightarrow$ Gametocytes formed $\rightarrow$ Mosquito ingests gametocytes $\rightarrow$ Sexual cycle in mosquito $\rightarrow$ Sporozoites develop.

• Protozoa (e.g., Amoebiasis):

Ingestion of cysts (contaminated food/water) $\rightarrow$ Excystation in intestine $\rightarrow$ Trophozoites invade colonic mucosa $\rightarrow$ Ulceration, dysentery $\rightarrow$ Haematogenous spread to liver (abscess).

• Helminths (e.g., Hookworm):

Larvae in soil $\rightarrow$ Penetrate skin $\rightarrow$ Migrate via blood to lungs $\rightarrow$ Cough up and swallow $\rightarrow$ Mature in small intestine $\rightarrow$ Attach to mucosa, feed on blood $\rightarrow$ Anaemia.

• Helminths (e.g., Schistosomiasis):

Cercariae in water $\rightarrow$ Penetrate skin $\rightarrow$ Migrate to lungs, then liver $\rightarrow$ Mature into adult worms in venules $\rightarrow$ Lay eggs $\rightarrow$ Eggs migrate to gut/bladder, causing inflammation and granuloma formation.

• Ectoparasites (e.g., Scabies):

Female mite burrows into stratum corneum $\rightarrow$ Lays eggs $\rightarrow$ Larvae hatch and migrate $\rightarrow$ Sensitization to mite antigens $\rightarrow$ Intense pruritus.

Clinical features

History questions that matter:

• Fever: Onset, duration, pattern (intermittent, continuous), associated chills, rigors, night sweats. Suggests systemic infection.
• Respiratory symptoms: Cough (productive/non-productive), sputum characteristics (colour, consistency, blood-stained), shortness of breath (onset, progression, exertional/at rest), chest pain (pleuritic/non-pleuritic). Common in pulmonary fungal infections (e.g., Pneumocystis, Cryptococcosis, Histoplasmosis) and parasitic infections (e.g., Paragonimiasis, strongyloidiasis hyperinfection).
• Neurological symptoms: Headache (onset, severity, character), neck stiffness, altered mental status (confusion, disorientation, lethargy), seizures, focal neurological deficits (weakness, sensory changes, visual disturbances). Crucial for CNS infections (e.g., Cryptococcal meningitis, cerebral toxoplasmosis, neurocysticercosis, cerebral malaria).
• Gastrointestinal symptoms: Abdominal pain (location, character, radiation), nausea, vomiting, diarrhoea (frequency, consistency, blood/mucus), constipation, weight loss, anorexia. Common in intestinal parasitic infections (e.g., amoebiasis, giardiasis, strongyloidiasis, ascariasis) and disseminated fungal infections.
• Skin lesions: Rashes (type, distribution, progression), nodules, ulcers, subcutaneous masses. Can indicate disseminated fungal infections (e.g., Cryptococcosis, Histoplasmosis, Sporotrichosis), cutaneous leishmaniasis, or larval migrans.
• Ocular symptoms: Blurred vision, pain, redness, photophobia. Important for ocular toxoplasmosis, onchocerciasis.
• Musculoskeletal symptoms: Joint pain, muscle aches, swelling. Can occur in disseminated infections.
• Genitourinary symptoms: Dysuria, frequency, haematuria, vaginal discharge. Relevant for urogenital schistosomiasis.
• Travel history: Recent travel to endemic areas (rural areas, specific regions within Kenya or neighbouring countries). Helps narrow down exposure.
• Exposure history: Contact with soil, bird/bat droppings, contaminated water/food, animals (cats for toxoplasmosis).
• Immunosuppression status: HIV status, CD4 count, ART adherence, history of TB, use of immunosuppressive medications (corticosteroids, chemotherapy), organ transplant. Critical for opportunistic infections.
• Previous infections/hospitalizations: Recurrent infections, previous diagnoses of fungal/parasitic diseases.

Examination findings and why each occurs:

• General appearance: Cachexia, pallor, jaundice. Indicates chronic illness, malnutrition, anaemia (e.g., hookworm), or liver involvement.
• Vital signs: Fever (systemic inflammation), tachycardia (fever, anaemia, sepsis), tachypnoea (respiratory distress, metabolic acidosis), hypotension (sepsis, shock).
• Skin:
  • Rashes, papules, nodules, ulcers: Direct manifestation of infection (e.g., Cryptococcal skin lesions, Kaposi's sarcoma in HIV, cutaneous leishmaniasis).
  • Jaundice: Liver dysfunction (e.g., severe malaria, amoebic liver abscess).
  • Pallor: Anaemia (e.g., hookworm, malaria).
  • Oedema: Hypoalbuminaemia (malnutrition, protein-losing enteropathy in some parasitic infections).
• Head and Neck:
  • Lymphadenopathy: Regional or generalized. Suggests systemic infection (e.g., Histoplasmosis, Toxoplasmosis, Leishmaniasis).
  • Neck stiffness: Meningeal irritation (e.g., Cryptococcal meningitis, cerebral toxoplasmosis).
  • Oral thrush (oral candidiasis): Immunosuppression, common in HIV.
  • Fundoscopy: Papilloedema (raised intracranial pressure), choroidoretinitis (e.g., ocular toxoplasmosis), retinal haemorrhages (e.g., severe malaria).
• Respiratory system:
  • Crepitations, rhonchi, dullness to percussion: Pulmonary consolidation, effusions, or interstitial infiltrates (e.g., Pneumocystis pneumonia, pulmonary Cryptococcosis, Paragonimiasis).
  • Increased work of breathing: Respiratory distress from lung involvement.
• Cardiovascular system:
  • Murmurs: Endocarditis (rare, but possible in disseminated fungal infections).
  • Tachycardia: Fever, anaemia.
• Abdomen:
  • Hepatomegaly, splenomegaly: Liver/spleen involvement (e.g., visceral leishmaniasis, schistosomiasis, severe malaria, disseminated fungal infections, amoebic liver abscess).
  • Tenderness, guarding, rebound tenderness: Peritonitis (e.g., bowel perforation in amoebiasis, strongyloidiasis hyperinfection).
  • Ascites: Portal hypertension (e.g., schistosomiasis), disseminated infection.
• Neurological system:
  • Altered mental status: Encephalopathy (e.g., cerebral malaria, Cryptococcal meningitis, cerebral toxoplasmosis).
  • Focal neurological deficits: Space-occupying lesions (e.g., cerebral toxoplasmosis, neurocysticercosis, cryptococcomas).
  • Meningeal signs (Kernig's, Brudzinski's): Meningitis (e.g., Cryptococcal meningitis).
  • Ataxia, tremors: Cerebellar involvement.

Differential diagnosis

Investigations

Diagnosis and severity

Diagnosis:

Diagnosis of fungal and parasitic infections relies on a combination of clinical suspicion, epidemiological factors, and laboratory confirmation.

1. Clinical suspicion: Based on characteristic symptoms, signs, and risk factors (especially immunosuppression, travel history, exposure).
2. Laboratory confirmation:
   • Direct visualization: Microscopy of clinical samples (blood, stool, CSF, sputum, skin scrapings, tissue biopsies) is often the cornerstone. Examples include India ink stain for Cryptococcus in CSF, Giemsa stain for Plasmodium in blood smears, wet mounts for Entamoeba or Giardia in stool.
   • Culture: Fungal cultures are essential for species identification and antifungal susceptibility testing, though they can be slow.
   • Antigen detection: Rapid and sensitive for some infections (e.g., Cryptococcal antigen in CSF/serum, Galactomannan for invasive aspergillosis, Histoplasma antigen in urine/serum).
   • Antibody detection: Indicates exposure or past infection (e.g., Toxoplasma IgG), but IgM can suggest acute infection. Less useful for acute diagnosis in immunocompromised.
   • Molecular methods (PCR): Highly sensitive and specific for detecting pathogen DNA/RNA in various samples (e.g., Pneumocystis jirovecii in BAL, Toxoplasma gondii in CSF, Leishmania in tissue).
   • Histopathology: Biopsy of affected tissue (skin, lung, lymph node, brain) can reveal characteristic fungal elements or parasitic forms and associated tissue reaction.

Severity:

Severity assessment guides immediate management and prognosis. Key indicators include:

• Systemic inflammatory response (SIRS) criteria: Fever/hypothermia, tachycardia, tachypnoea, leukocytosis/leukopenia. Presence of SIRS suggests systemic infection.
• Organ dysfunction:
  • Respiratory: Hypoxia, respiratory distress, need for oxygen/ventilatory support.
  • Neurological: Altered mental status (GCS score), seizures, focal neurological deficits, signs of raised intracranial pressure.
  • Renal: Acute kidney injury (elevated creatinine, oliguria).
  • Hepatic: Liver enzyme derangements, jaundice, coagulopathy.
  • Cardiovascular: Hypotension, shock.
• Immunosuppression status: Lower CD4 counts in HIV patients correlate with higher risk of severe opportunistic infections and poorer outcomes.
• Parasite load/fungal burden: High parasite density in malaria, high Cryptococcal antigen titres, or extensive fungal growth in cultures often indicate higher disease burden and severity.
• Complications: Presence of specific complications like acute respiratory distress syndrome (ARDS), cerebral oedema, bowel perforation, or disseminated intravascular coagulation (DIC).
• Functional status: Ability to perform daily activities, mobility.

Management

Immediate Stabilisation:

• Airway, Breathing, Circulation (ABC): Ensure patent airway, adequate ventilation, and haemodynamic stability. This is paramount in critically ill patients with severe infections, especially those with sepsis or significant anaemia from parasitic infections.
• Fluid Resuscitation: For hypotensive patients, administer intravenous fluids judiciously.
• Symptomatic Relief: Address fever with antipyretics, pain with analgesics, and vomiting with antiemetics.
• Nutritional Support: Early initiation of adequate nutrition is crucial, especially for malnourished patients or those with prolonged illness.

Definitive Treatment:

• Antifungal Therapy:
  • Superficial Fungal Infections: Topical agents (e.g., azoles, nystatin) are usually sufficient.
  • Systemic Fungal Infections:
    • Azoles (e.g., fluconazole, itraconazole): Broad-spectrum, often first-line for candidiasis and cryptococcosis.
    • Amphotericin B (lipid formulations preferred for reduced toxicity): Reserved for severe, life-threatening infections or those refractory to azoles.
    • Echinocandins (e.g., caspofungin): Effective against Candida species, particularly useful in azole-resistant infections.
    • Specific agents: For infections like aspergillosis (e.g., voriconazole) or mucormycosis (e.g., posaconazole, amphotericin B).
• Antiparasitic Therapy:
  • Protozoal Infections:
    • Malaria: Artemisinin-based combination therapies (ACTs) are the mainstay. Specific drug choices depend on the Plasmodium species and local resistance patterns.
    • Amoebiasis: Metronidazole for invasive disease, followed by a luminal agent (e.g., paromomycin) for asymptomatic carriers.
    • Giardiasis: Metronidazole or tinidazole.
    • Toxoplasmosis: Pyrimethamine and sulfadiazine, often with leucovorin rescue, especially in immunocompromised individuals.
    • Cryptosporidiosis: Nitazoxanide in immunocompetent individuals; supportive care is key in immunocompromised.
  • Helminthic Infections:
    • Intestinal Nematodes (e.g., Ascaris, hookworm, Trichuris): Albendazole or mebendazole.
    • Schistosomiasis: Praziquantel.
    • Taeniasis: Praziquantel or niclosamide.
    • Cysticercosis: Praziquantel or albendazole, often with corticosteroids and anti-epileptics.
    • Filariasis: Diethylcarbamazine (DEC) for lymphatic filariasis; ivermectin for onchocerciasis.
• Management of Co-infections: Aggressively treat concurrent infections like HIV, TB, and malaria, as they significantly impact prognosis and treatment response. Antiretroviral therapy (ART) is crucial for HIV-positive patients.

Monitoring and Follow-up:

• Clinical Response: Monitor for improvement in symptoms, signs, and overall well-being.
• Laboratory Parameters: Repeat relevant investigations (e.g., blood counts, parasite counts, fungal markers) to assess treatment efficacy and detect relapse.
• Adverse Drug Reactions: Vigilantly monitor for side effects of antifungal and antiparasitic agents.
• Nutritional Status: Regular assessment and support.
• Prophylaxis: Consider prophylactic antifungals or antiparasitics in severely immunocompromised patients or those at high risk of specific infections.

Contraindications and Safety:

• Allergies: Document and avoid known allergens.
• Renal and Hepatic Impairment: Adjust drug dosages as necessary.
• Pregnancy and Lactation: Many antifungals and antiparasitics are contraindicated or require careful risk-benefit assessment.
• Drug Interactions: Be aware of potential interactions between antifungals/antiparasitics and other medications.
• Toxicity: Monitor for specific toxicities associated with certain drugs (e.g., nephrotoxicity with amphotericin B, neurotoxicity with metronidazole).

Complications and Prognosis

Complications:

• Disseminated Infections: Fungal or parasitic infections can spread hematogenously to multiple organs, leading to organ dysfunction and failure.
• Sepsis and Septic Shock: Severe infections can trigger a systemic inflammatory response.
• Organ Damage: Chronic or severe infections can cause irreversible damage to the liver, kidneys, lungs, brain, or heart.
• Malnutrition and Wasting: Particularly common with chronic parasitic infections.
• Anaemia: Significant blood loss from hookworm or schistosomiasis, or bone marrow suppression from certain infections.
• Neurological Sequelae: Neurocysticercosis, cerebral malaria, or fungal meningitis can lead to seizures, cognitive deficits, or paralysis.
• Secondary Bacterial Infections: Compromised immunity or tissue damage can predispose to bacterial superinfections.
• Drug Resistance: Inadequate treatment or poor adherence can lead to the development of resistant strains.

Prognosis: The prognosis varies widely depending on the specific pathogen, the host's immune status, the severity of the infection, and the promptness and appropriateness of treatment.

• Superficial fungal infections: Generally excellent prognosis with appropriate topical therapy.
• Systemic fungal infections: Can be life-threatening, especially in immunocompromised individuals. Prognosis improves with early diagnosis and effective treatment.
• Protozoal infections: Varies from curable (e.g., amoebiasis) to potentially fatal (e.g., severe malaria, cryptococcal meningitis in HIV).
• Helminthic infections: Generally good prognosis with antiparasitic treatment, but chronic infections can lead to significant morbidity. Complications like intestinal obstruction or anaemia can worsen outcomes.
• Co-infections (HIV, TB): Significantly worsen prognosis and require integrated management.

High-Yield Exam Points

• Look-alike Conditions:
  • Malaria vs. Dengue: Both present with fever, myalgia, and headache. Malaria has characteristic cyclical fevers and potential for splenomegaly; dengue may have rash and retro-orbital pain.
  • Amoebic Liver Abscess vs. Pyogenic Liver Abscess: Clinical presentation can be similar. Amoebic abscesses are often single, with a history of dysentery. Pyogenic abscesses may have a clear source of infection (e.g., cholangitis).
  • Candidiasis vs. Bacterial Pneumonia: In immunocompromised patients, differentiating these can be challenging based on symptoms alone. Sputum microscopy and cultures are key.
• Commonest Wrong First Steps:
  • Starting broad-spectrum antibiotics without considering fungal or parasitic causes in an immunocompromised patient with fever.
  • Treating fever with antipyretics alone without investigating the underlying cause.
  • Delaying antiparasitic treatment for severe helminthic infections due to concerns about "worm burden" migration.
• Examiner Questions at Bedside:
  • "What are the most likely parasitic/fungal causes of fever in this patient, given their history and immune status?"
  • "What specific examination findings would support your suspected diagnosis?"
  • "What are the immediate management priorities for this patient?"
  • "What investigations would you order, and why?"
  • "What are the potential complications of this infection, and how would you monitor for them?"
  • "How would you counsel the patient regarding treatment and follow-up?"

Clinical Case

A 45-year-old male, known to be HIV-positive with a recent CD4 count of 80 cells/µL, presents with a two-week history of progressive shortness of breath, non-productive cough, and low-grade fever. He also reports diffuse headaches and photophobia. On examination, he is febrile, tachypneic, with diffuse crackles on auscultation. His neck is supple, and there are no focal neurological deficits.

Questions:

1. What is the most likely diagnosis, and what is the immediate management priority?
2. What investigations would you perform to confirm your diagnosis and assess severity?
3. What is the definitive management for this condition, and what are the key monitoring parameters?

Model Answers:

1. The most likely diagnosis is cryptococcal meningitis and/or cryptococcal pneumonia, given his profound immunosuppression (low CD4 count) and the constellation of symptoms (respiratory, fever, headache, photophobia). The immediate management priority is resuscitation and initiation of empiric antifungal therapy, along with consideration for lumbar puncture if safe.
2. Investigations should include: Complete Blood Count (CBC) to assess for anaemia or leukocytosis; HIV viral load and CD4 count (if not recent); Chest X-ray to evaluate for pneumonia; Sputum microscopy and India ink stain for Cryptococcus; Lumbar puncture for Cerebrospinal Fluid (CSF) analysis including India ink stain, cryptococcal antigen testing, and cell count/differential; Blood cultures to rule out bacteremia; Serum cryptococcal antigen.
3. Definitive management involves antifungal therapy, typically starting with amphotericin B (lipid formulation) and flucytosine for induction, followed by a consolidation phase with fluconazole. Monitoring parameters include clinical improvement (resolution of fever, headache, respiratory symptoms), CSF parameters (decreasing fungal load, antigen titres), and potential adverse effects of medications (renal function, bone marrow suppression).

Practice Questions

Question 1

A 60-year-old woman with poorly controlled diabetes presents with a 3-day history of severe headache, fever, and purulent nasal discharge. On examination, she has proptosis of the right eye and a necrotic lesion on the nasal septum. Her blood glucose is significantly elevated. What is the most appropriate next step in management?

A. Start broad-spectrum antibiotics B. Initiate empiric antifungal therapy with fluconazole C. Urgent surgical debridement of the necrotic tissue D. Obtain a CT scan of the sinuses and orbits

Answer: D. Obtain a CT scan of the sinuses and orbits Explanation: The clinical presentation is highly suggestive of mucormycosis, a rapidly invasive fungal infection common in diabetics. Imaging is crucial to assess the extent of disease and guide surgical and medical management.

Question 2

A 30-year-old man from a rural area presents with a two-week history of intermittent fever, abdominal pain, and passage of dark, tarry stools. He is pale and appears anaemic. His stool microscopy reveals ova of Ancylostoma duodenale. What is the most appropriate treatment?

A. Praziquantel B. Metronidazole C. Albendazole D. Ivermectin

Answer: C. Albendazole Explanation: Albendazole is the drug of choice for treating intestinal nematode infections like hookworm (Ancylostoma duodenale), which is causing his anaemia and blood loss.

Question 3

A 55-year-old HIV-positive patient with a CD4 count of 50 cells/µL develops a diffuse, maculopapular rash and fever after starting antiretroviral therapy (ART). He also complains of mild nausea. Which of the following is the most likely diagnosis?

A. Cryptosporidiosis B. Drug reaction C. Cytomegalovirus (CMV) infection D. Toxoplasmosis

Answer: B. Drug reaction Explanation: The timing of the rash and fever after starting ART in an immunocompromised patient is highly suggestive of an immune reconstitution inflammatory syndrome (IRIS) or a direct drug reaction, rather than a new opportunistic infection.

Question 4

Which of the following parasitic infections is primarily transmitted through the ingestion of undercooked meat containing larval cysts?

A. Schistosomiasis B. Giardiasis C. Taeniasis solium (pork tapeworm) D. Ascariasis

Answer: C. Taeniasis solium (pork tapeworm) Explanation: Ingesting undercooked pork containing cysticerci leads to intestinal taeniasis. Ingestion of eggs (e.g., from contaminated food or water) can lead to cysticercosis, a more serious condition.

Question 5

A patient presents with a history of dysentery, followed by the development of a painful, enlarged liver with a palpable, tender mass. Ultrasound shows a unilocular, well-defined cystic lesion. Which of the following is the most likely causative organism?

A. Entamoeba histolytica B. Giardia lamblia C. Plasmodium falciparum D. Candida albicans

Answer: A. Entamoeba histolytica Explanation: Entamoeba histolytica is the causative agent of amoebiasis, which can lead to amoebic liver abscesses presenting with fever, hepatomegaly, and pain, often following a history of dysentery.

Drafted with AI assistance from standard references and reviewed for structure. Check details against your lecture notes and the Kenya MoH guideline.