Ancylostoma is a genus of nematodes, also known as hookworms. They have been described in many non-human primate hosts. The main species affecting non-human primates is Ancylostoma duodenale. This species has also been described in humans (Strait et al., 2012).

Epidemiology

Ancylostoma nematodes can be found in Africa, Asia, and the Americas. The species Ancylostoma duodenale is reported to affect apes (Hylobatidae, Pan spp., Gorilla spp.) (Strait et al., 2012; Murphy, 2015) and Old-World Monkeys (Mandrillus spp., Papio spp., Cercopithecus spp., Procolobus badius, Procolobus verus, Colobus polykomos, Cercocebus atys, Macaca mulatta) (Calle & Joslin, 2015; Kouassi et al., 2015; Strait et al., 2015). However, other species of Ancylostoma may also affect New World Monkeys (Strait et al., 2012; Calle & Joslin, 2015; Murphy, 2015).

Description

Ancylostoma eggs have a characteristic morphology: they are oval with large tips and measure 56 to 76 µm long and 36 to 40 µm large. Moreover, they have a thin outer membrane and contain a translucid morula with 4 to 8 blastomeres (Garcia, 2021). They cannot be differentiated from Necator americanus eggs on coproscopic examination. Moreover, ovodiagnosis does not allow differentiation between species of Ancylostoma (Garcia, 2021).

Differential diagnosis

The main differential diagnosis for Ancylotoma spp. is Necator americanus. To a larger extent, Ancylostoma eggs need to be differentiated from non-embryonated strongyle eggs (Strait et al., 2012).

Clinical significance

Ancylostoma duodenale has been described to cause clinical signs in both non-human primates and humans: it is a zoonotic pathogen. It can cause anemia, eosinophilia, expiratory dyspnea, abdominal distension, and general weakness (Strait et al., 2012).

Prophylaxis and treatment

As Ancylostoma duodenale is reported to be zoonotic, hygienic measures need to be taken in case of diagnosis.

Various treatments have been described to treat hookworm infections in non-human primates, namely:

• Ivermectin: 200 µg/kg IM once, repeated 3 weeks later if necessary (Strait et al., 2012);
• Tetramisole: 12-16 mg/kg PO once (Strait et al., 2012);
• Mebendazole: 15 mg/kg PO q24h during 2 days OR 4 mg/kg PO q24h during 10 days (Strait et al., 2012);
• Levamisole: 7.5 mg/kg SC twice two weeks apart (Strait et al., 2012);
• Fenbendazole: 25 mg/kg PO twice one week apart (Calle & Joslin, 2015).