Malarial parasites with 48 hr cycle are

Options

A. Plasmodium malariae, P. falciparum and P. ovale
B. Plasmodium malariae, P. falciparum and P. vivax
C. Plasmodium malariae, P. ovale and P. vivax
D. Plasmodium falciparum, P. ovale and P. vivax.

Answer

To determine which malarial parasites have a 48-hour cycle, we need to analyze the different species of the Plasmodium genus and their respective life cycles. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Malarial Parasites
The main species of Plasmodium that cause malaria in humans are:
- Plasmodium falciparum
- Plasmodium vivax
- Plasmodium ovale
- Plasmodium malariae

### Step 2: Understand the Life Cycles
Next, we need to understand the life cycles of these species:
- **Plasmodium falciparum**: This species has a life cycle of approximately 48 hours and is known for causing severe malaria.
- **Plasmodium vivax**: This species also has a life cycle of about 48 hours and is the main cause of recurring malaria.
- **Plasmodium ovale**: This species has a life cycle that ranges from 48 to 50 hours, which can still be considered as 48 hours for this context.
- **Plasmodium malariae**: This species has a longer life cycle of approximately 72 hours, which is not relevant to our question.

### Step 3: Analyze the Options
Now, let's analyze the options provided in the question:
1. Plasmodium malaria, falciparum, and ovale
2. Plasmodium malaria, falciparum, and vivax
3. Plasmodium malaria, ovale, and vivax
4. Plasmodium falciparum, ovale, and vivax

From the analysis:
- Options 1, 2, and 3 include Plasmodium malariae, which has a 72-hour cycle, making them incorrect.
- Option 4 includes only Plasmodium falciparum, ovale, and vivax, all of which have a life cycle of 48 hours.

### Conclusion
Thus, the correct answer is **Option 4: Plasmodium falciparum, ovale, and vivax**, as all these parasites have a life cycle of approximately 48 hours.

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