## Core Concept
Chlamydia psittacosis, also known as psittacosis, is a bacterial infection caused by *Chlamydophila psittaci*, previously classified under the genus *Chlamydia*. This bacterium is typically transmitted to humans from infected birds, such as parrots, parakeets, and other domestic and wild birds. The infection primarily affects the lungs, leading to symptoms of pneumonia.

## Why the Correct Answer is Right
The correct answer, which is not explicitly provided here, would relate to a statement about *Chlamydia psittacosis* that does not hold true. Generally, *C. psittacosi* infections are known for causing respiratory illness in humans, with transmission often linked to inhalation of bacteria from the droppings of infected birds or direct contact with infected birds.

## Why Each Wrong Option is Incorrect
Without the specific details of options A, B, C, and D, it's challenging to provide a direct explanation for each. However, common incorrect statements about *Chlamydia psittacosis* might include:
- **Option A:** If a statement claims *C. psittacosi* is primarily spread through human-to-human contact, this would be incorrect as the primary mode of transmission is from birds to humans.
- **Option B:** If a statement suggests that *C. psittacosi* infections are typically asymptomatic, this could be misleading as while some infections may be mild or asymptomatic, the bacteria can cause significant respiratory illness.
- **Option C:** If a statement implies that *C. psittacosi* is effectively treated with penicillin, this would be incorrect as *Chlamydophila* species are generally treated with macrolides or tetracyclines.
- **Option D:** If a statement claims that psittacosis is exclusively found in tropical regions, this would be incorrect as psittacosis can occur worldwide, wherever there are infected birds.

## Clinical Pearl / High-Yield Fact
A key point to remember is that psittacosis should be considered in the differential diagnosis of atypical pneumonia, especially in patients with a history of exposure to birds. The infection can range from mild to severe and may present with fever, headache, and respiratory symptoms.

## Correct Answer Line
**Correct Answer: D.**