Moniliformis

Moniliformis moniliformis

Moniliformis saudi

Acanthocephala LifeCycle lg

Common spiny mouse

Four-toes-jerboa

Atelerix algirus

Moniliformis is a genus of parasitic Acanthocephala, a group of helminth organisms commonly referred to as thorny-headed worms, due to their characteristic spiny proboscis. These parasites are known for their unique life cycle, involving arthropods as intermediate hosts and vertebrates, typically mammals and occasionally birds, as definitive hosts. Moniliformis species are of interest in both veterinary and medical parasitology due to their impact on host health and their zoonotic potential, although human infections are relatively rare.

Description

Moniliformis parasites are characterized by their elongated, cylindrical bodies, which give them a worm-like appearance. The most distinctive feature of these organisms is their proboscis, which is covered in rows of hooks. This structure is used to anchor the parasite to the intestinal wall of the host. The body of Moniliformis may appear segmented, which is the origin of its name (moniliformis meaning "necklace-like" in Latin), although these segments are not true metameres as seen in annelids.

Life Cycle

The life cycle of Moniliformis involves two hosts: an intermediate host, which is usually an arthropod such as a cockroach or beetle, and a definitive host, which is a vertebrate. The eggs of the parasite are expelled with the feces of the definitive host and must be ingested by the intermediate host to continue the cycle. Within the intermediate host, the eggs hatch into larval forms known as acanthors, which then develop into acanthellae and finally into infective cystacanths. When the infected intermediate host is consumed by a suitable definitive host, the cystacanths excyst in the vertebrate's intestine, where they mature into adult parasites and the cycle begins anew.

Pathogenicity

In definitive hosts, Moniliformis infections can lead to a variety of symptoms, primarily associated with gastrointestinal distress. Heavy infestations can cause significant damage to the intestinal wall, leading to malabsorption, weight loss, and in severe cases, perforation of the intestine. In intermediate hosts, the presence of larval stages can cause physical damage and may affect the host's behavior, making it more likely to be predated by the definitive host.

Diagnosis and Treatment

Diagnosis of Moniliformis infection in definitive hosts is typically made by the identification of eggs or adult worms in fecal samples. In intermediate hosts, diagnosis may involve the detection of larval stages in tissues. Treatment usually involves the administration of anthelmintic drugs, which can effectively eliminate the parasites. Preventative measures include controlling intermediate host populations and avoiding the consumption of raw or undercooked foods that may contain infective stages.

Epidemiology

Moniliformis infections are more common in regions where close contact between humans and potential intermediate hosts occurs, particularly in areas with poor sanitation. Infections in humans are rare but have been reported, underscoring the zoonotic potential of these parasites. The epidemiology of Moniliformis infections is closely tied to the ecology of the intermediate hosts, making environmental changes and human behavior significant factors in the transmission dynamics of these parasites.