a) The parasite that caused the girl’s disease is cysticercus, which is the larval form of the tapeworm Taenia solium. This parasite is transmitted through the ingestion of contaminated food or water that contains the eggs of the tapeworm. In this case, the girl likely ingested food or water contaminated with the eggs of the tapeworm within South Carolina.
To prevent this disease, it is important to practice good hygiene and food safety measures. This includes proper handwashing, especially before handling food, and thorough cooking of meat, as tapeworm larvae can be present in raw or undercooked pork. Additionally, maintaining proper sanitation and hygiene in areas where pigs are raised can also help prevent the transmission of the parasite.
b) The most likely organism causing the farmer’s symptoms is the fungus Coccidioides immitis, which causes the disease known as coccidioidomycosis or Valley fever. This fungus is found in the soil of certain regions, including California, and can be inhaled when the soil is disturbed, leading to infection.
To prevent this disease, individuals in high-risk areas should try to avoid activities that can lead to exposure to the fungus, such as digging or working in dusty environments. Wearing masks and protective clothing in such environments can also help reduce the risk of infection.
c) The disease that the teenage male in California has is malaria, specifically caused by the parasite Plasmodium vivax. Malaria is acquired through the bite of infected female Anopheles mosquitoes. Since the patient has no history of foreign travel, blood transfusion, or intravenous drug use, it is likely that he acquired the infection locally from a mosquito bite near the San Luis Rey River.
To prevent malaria, it is important to take measures to avoid mosquito bites, such as using insect repellent, wearing protective clothing, and sleeping under bed nets. In addition, efforts to control mosquitoes and their breeding sites can help reduce the transmission of the disease.
d) The disease that the HIV-positive man is experiencing is Pneumocystis pneumonia (PCP), which is caused by the fungus Pneumocystis jirovecii. PCP is a common opportunistic infection in individuals with weakened immune systems, such as those with HIV.
The virus that causes this disease is the Human herpesvirus 8 (HHV-8), also known as Kaposi’s sarcoma-associated herpesvirus. A viral culture was done after the Gram and acid-fast stain results were obtained in order to identify the specific virus causing the symptoms.
Viral cultures are often done when other laboratory tests are inconclusive or do not provide enough information to identify the cause of the disease. In this case, the Gram and acid-fast stains were done to rule out bacterial and mycobacterial infections, respectively, before proceeding with the viral culture.
e) The most likely viral cause of the newborn’s extensive vesicular and ulcerative lesions over her face and chest is the Herpes simplex virus (HSV). This virus is commonly associated with skin and mucous membrane infections, including cold sores and genital herpes.
To determine the viral cause of this disease without doing a viral culture, other laboratory tests can be used, such as polymerase chain reaction (PCR) or serological tests. PCR can detect the presence of viral DNA or RNA in a sample, while serological tests can detect the presence of specific antibodies against the virus in the blood. These tests can provide rapid and accurate diagnosis without requiring a viral culture.
f) The disease described in the household with a high mortality rate is Hantavirus pulmonary syndrome (HPS). This disease is caused by members of the family Bunyaviridae, specifically hantaviruses. Hantaviruses are zoonotic viruses that are primarily transmitted to humans through the inhalation of aerosolized urine, feces, or saliva from infected rodents, particularly mice.
The main difference between the mentioned viral families is their method of transmission, morphology, nucleic acid, and type of replication.
– Orthomyxoviridae: This family includes the influenza viruses, which are primarily transmitted through respiratory droplets. The viruses in this family have a negative-sense, single-stranded RNA genome and replicate in the host cell nucleus.
– Bunyaviridae: This family includes various pathogens, including hantaviruses, which are primarily transmitted through contact with infected rodents or their excretions. The viruses in this family have a negative-sense, single-stranded RNA genome and replicate in the cytoplasm of the host cell.
– Adenoviridae: This family includes the adenoviruses, which are primarily transmitted through respiratory droplets, fecal-oral route, or contact with contaminated surfaces. The viruses in this family have a double-stranded DNA genome and replicate in the nucleus of the host cell.
The reservoir for HPS is mice, specifically the deer mouse (Peromyscus maniculatus) in North America.
