On a new nematode Leipernema leiperi n.g., n.sp. (Strongyloididae), parasitic in the pangolin Manis pentadactyla from Hyderabad, India

Molecular detection of a novel Ancylostoma sp. by whole mtDNA sequence from pangolin Manis javanica

Background

Ancylostoma species are hematophagous parasites that cause chronic hemorrhage in various animals and humans. Pangolins, also known as scaly anteaters, are mammals that live in soil environments where they are readily exposed to soil-borne parasitic nematodes. However, only a limited number of helminth species have been identified in this animal host so far.

Methods

Ancylostoma sp. was isolated from a wild pangolin, and the complete mitochondrial (mt) genome of Ancylostoma sp. was obtained by Illumina sequencing of total genomic DNA.

Results

The circular complete mt genome that was assembled had a total length of 13,757 bp and comprised 12 protein-coding genes (PCGs), 22 transfer ribosomal RNAs, two ribosomal RNAs (rRNAs), two non-coding regions and one AT-rich region, but lacked the gene coding for ATPase subunit 8 (atp8). The overall AT content of the mt genome of Ancylostoma sp. was 76%, which is similar to that of other nematodes. The PCGs used two start codons (ATT and TTG) and three stop codons (TAA, TAG, and T). The nucleotide identity of the 12 PCGs ranged from 83.1% to 89.7% and had the highest sequence identity with Ancylostoma caninum among species in the Ancylostomatidae family. Also, the pangolin-derived Ancylostoma sp. lacked repeat sequences in the non-coding regions and in the unique sequence of the short non-coding regions, which differentiated it from other Ancylostoma species. In addition, phylogenetic analyses of 18S rRNA and mtDNA sequences revealed that the Ancylostoma sp. was positioned in a separate branch in the subfamily Ancylostomatinae along with other Ancylostoma species.

Conclusions

The Ancylostoma sp. isolated from a pangolin in this study was identified as a possible new Ancylostoma species. The identification of this Ancylostoma sp. from pangolin enriches our knowledge of the species in the Ancylostomatidae family and provides information that will lead to a better understanding of the taxonomy, diagnostics, and biology of hookworms.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05191-0.

A Review of the Parasite Fauna of the Black-Bellied Pangolin, Phataginus tetradactyla LIN. (Manidae), From Central Africa with the Description of Intraproboscis sanghae n. gen., n. sp. (Acanthocephala: Gigantorhynchidae)

A new archiacanthocephalan in the family Gigantorhynchidae, Intraproboscis sanghae n. gen., n. sp. is described from females collected from the African black-bellied pangolin Phataginus tetradactyla Linn. (Manidae) in the Central African Republic. A dichotomous key to the genera of Gigantorhynchidae is provided. The specimens presented are distinct from those of the genus Gigantorhynchus Hamann, 1892 that have only 1 or 2 circles of hooks (crowns) at the apical end of the proboscis and are found in South American mammals, except for Gigantorhynchus pesteri Tadros, 1966 from baboons in Rhodesia (Zimbabwe), Africa (Amin, 2013). They superficially resemble those of the other gigantorhynchid genus Mediorhynchus Van Cleave, 1916, especially in the organization of the truncate-cone proboscis and the position of the receptacle. Species of Mediorhynchus are bird parasites. The new genus, Intraproboscis, now the third genus in Gigantorhynchidae; however, is distinguished from Mediorhynchus by having a simple proboscis receptacle that is completely suspended within the proboscis, the passage of the retractor muscles through the receptacle into the body cavity posteriorly, absence of neck, and presence of a parareceptacle structure (first finding in the Archiacanthocephala) and a uterine vesicle; among other features, including the differential dorsoventral thickness of the body wall. The receptacle in Mediorhynchus is complex, with many accessory muscles and retractor muscles passing into the body cavity dorsally and ventrally. Our specimens reached 180 mm in length and the proboscis had 34-36 rows of 6-7 ventrally lamellated, rooted hooks each anteriorly, and 15-17 spinelike hooks each posteriorly. Micropores extended into the anterior and posterior proboscis and energy dispersive x-ray analysis (EDXA) of anterior hooks showed high levels of calcium and phosphorus but negligible traces of sulfur. Spinelike hooks in the posterior proboscis had lower levels of Ca and P and slightly higher levels of S. Molecular and phylogenetic analyses based on the 18S rDNA gene placed I. sanghae in a clade with the archiacanthocephalans Mediorhynchus, Moniliformis, Macracanthorhynchus, Oncicola, and Oligacanthorhynchus.

Check list of parasites and bacteria recorded from pangolins (Manis sp.)

Sound knowledge on parasite fauna of pangolins is crucial for evaluation of their health status. In the present review, a checklist of 34 genera of parasites and bacteria, including 4 genera of protozoan, 13 genera of helminthes, 8 genera of ticks, 2 genera of mites and 7 genera of bacteria reported from pangolins was compiled and their zoonotic potential were discussed. The aim of this checklist is to underline the information gap and to provide a reference list of parasites and bacteria known for pangolins to assist in their further investigation.