Zoonotic Rat Lungworm Angiostrongylus cantonensis in Black Rats, Houston, Texas, 2024

Abstract

The Angiostrongylus cantonensis rat lungworm is a zoonotic nematode that infects several rat species. This nematode causes eosinophilic meningitis and meningoencephalitis in humans and other accidental hosts. We found a 20% prevalence of A. cantonensis lungworms in black rats from a zoo facility in Houston, Texas, USA.

Keywords: Angiostrongylus cantonensis; Rat lungworm; Rattus rattus; Texas; United States; black rats; parasites; zoonoses.

Figure 1

Histopathology of Angiostrongylus cantonensis rat lungworm infection in metropolitan black rats, Houston, Texas, 2024. A) Severe pulmonary consolidation due to verminous pneumonia. Adult nematode is visible within a large artery (arrow). Scale bar = 1.5 mm. B) Higher magnification of lung with numerous A. cantonensis larvae and eggs surrounded by granulomatous inflammation. Scale bar = 80 µm. C) Multiple adult A. cantonensis nematodes in right ventricle of the heart. Scale bar = 1.5 mm. D) Mild lymphoplasmacytic meningitis with cross sections of A. cantonensis nematodes. Scale bar = 300 µm.

Figure 2

Maximum-likelihood phylogenetic tree (1,000 bootstrap replicates) from study of zoonotic rat lungworm Angiostrongylus cantonensis in black rats, Houston, Texas, 2024. Tree depicts the phylogenetic relationships of A. cantonensis sequences generated from samples in this study and representative sequences of A. cantonensis haplotypes from the United States and globally. Sequences generated in the study are labeled HZR and were deposited into GenBank (accession nos. PQ556202–29). Reference sequences are identified by GenBank accession number and location.