Which of the following is a carrying agent for the disease with given characteristics on polarized microscopy?
Ixodes scapularis ticks
Answer: B. Ixodes scapularis ticks
- Babesiosis infects the RBCs and resides inside the RBCs ( intraerythrocytic).
- Intraerythrocytic infection of Babesiosis is characterized by the maltese cross.
- The Maltese cross is a characteristic arrangement of parasites within the erythrocytes → Parasites within erythrocytes are arranged such that pointed ends of four parasites come in contact thereby giving a tetrad configuration resembling a maltese cross.
- Tetrad forms or ‘Maltese cross’ appearance is considered pathognomonic of Babesiosis.
- Babesiosis can easily be confused with P. falciparum malaria. Following two features distinguish Babesiosis from malaria
- Presence of maltese cross in Babesiosis ( absent in malaria)
- Absence of pigment Hemozoin in Babesiosis ( present in malaria)
Note – Maltese cross is also seen in cryptococcus and aspergillus.