Antiparasitic, Insecticidal, and Larvicidal Activities of Seaweeds and their Extracts
Leonel Pereira in Therapeutic and Nutritional Uses of Algae, 2018
Eight known filarial nematodes use humans as their definitive hosts. These are divided into three groups according to the niche they occupy in the body—Lymphatic filariasis is caused by the worms Wuchereria bancrofti, Brugia malayi, and Brugia timori.These worms occupy the lymphatic system, including the lymph nodes; in chronic cases, these worms lead to the syndrome of elephantiasis;Subcutaneous filariasis is caused by Loa loa (the eye worm),Mansonella streptocerca, and Onchocerca volvulus. These worms occupy the subcutaneous layer of the skin, in the fat layer. L. loa causes Loa loa filariasis, while O. volvulus causes river blindness;Serous cavity filariasis is caused by the worms Mansonella perstans and Mansonella ozzardi, which occupy the serous cavity of the abdomen.
The Parasite's Way of Life
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2023
Recent advances in genomics and transcriptomics are helping to further clarify the manner in which parasites recognize certain host physiological cues and utilize them in their migration. Phylum-wide genomic analysis in nematodes, for instance, confirms the fact that parasites have a greatly reduced complement of genes encoding chemoreceptors compared to free living species, although most of the downstream molecules involved with signaling pathways are retained. Furthermore, at least in certain filarial worms, including Brugia malayi (see the Rogues’ Gallery for a description of its life cycle and migratory route through its hosts), a species causing human filariasis, different chemoreceptors are expressed at different points in the parasite’s migration. These chemoreceptors belong to the G-protein linked receptor family and are found on specialized cilia in amphids, which are anterior innervated, invaginations of the cuticle serving as chemosensory organs in nematodes. Although many questions remain, these results suggest that different chemoreceptors recognize different host ligand molecules at key points in parasite migration, helping to guide the parasite through both its mosquito intermediate and human definitive hosts.
The Parasitic Protozoa and Helminth Worms
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
Human filariasis is caused by infections with several species of nematode worms, the females of which produce larvae that are released in the body of the host, often in the blood, until taken up by an arthropod vector. The most important manifestations are lymphatic filariasis and onchocerciasis. In lymphatic filariasis, caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori and transmitted by mosquitoes, the adults live in the lymphatics, and the disease is characterized by lymphatic blockage resulting in swelling of the limbs, scrotum and other parts of the body causing the condition known as elephantiasis. In onchocerciasis, caused by Onchocerca volvulus and transmitted by blackflies belonging to the genus Simulium, the adults live in skin nodules, and the disease is characterized by blindness.
Helminths, hosts, and their microbiota: new avenues for managing gastrointestinal helminthiases in ruminants
Published in Expert Review of Anti-infective Therapy, 2020
Alba Cortés, James Rooney, Dave J. Bartley, Alasdair J. Nisbet, Cinzia Cantacessi
Together with increasing evidence of a fundamental role of the host gut flora in mechanisms of worm infection and establishment [9,10], several studies are beginning to elucidate the relative contribution of a ‘parasite microbiome’ to several physiological and reproductive processes of worms [60]. Indeed, endosymbionts have long been known to exert key functions in the biology of nematodes causing lymphatic filariasis in humans, i.e. Wuchereria bancrofti, Brugia malayi, and Brugia timori. These parasites harbor an obligate alpha-proteobacterial endosymbiont (Wolbachia) that is essential for worm development and survival, likely via the provision of pyrimidines [61]. The discovery that removal of Wolbachia using antibiotics led to effective control of filarial nematodes triggered a number of drug discovery programmes to develop novel, safe, and specific antiwolbachial drugs [62], as well as vaccines targeting Wolbachia antigens (e.g. [63]). One of these molecules, a Recombinase A of Wolbachia from B. malayi (wBmRecA), has shown some promise as a protective antigen against filarial infections; indeed, mice immunized with a recombinant version of wBmRecA and subsequently challenged with B. malayi microfilariae harbored 64.5% fewer infective third-stage (L3) larvae at postmortem examination than mice immunized with adjuvant only [63].
In vivo activity and atom pair fingerprint analysis of MMV665941 against the apicomplexan parasite Babesia microti, the causative agent of babesiosis in humans and rodents
Published in Pathogens and Global Health, 2023
Mohamed Abdo Rizk, Shimaa Abd El-Salam El-Sayed, Ikuo Igarashi
MMV665941 was also found to be effective against some strains of Perkinsus marinus, a major protozoal disease of oysters, however the efficiency was not uniform across all strains of the parasite [23]. Brugia malayi and B. pahangi, as well as Cryptosporidium, Tritrichomonas foetus trophozoites, and Trypanosoma cruzi, have all been proven to be susceptible to this chemical [24–27]. MMV665941 has a structural similarity to gentian violet. In addition to being utilized as a mold inhibitor in feed components, gentian violet has been employed in human medicine for illnesses with a variety of bacteria [28]. In the United States, however, gentian violet is strictly prohibited for use in any food animal [29]. Interestingly, there have been few grounds given for the gentian violet prohibition, other than the FDA’s statement that the impact of drug residues on human health has not been sufficiently studied [29].
Lymphatic filariasis vaccine development: neglected for how long?
Published in Expert Review of Vaccines, 2021
Vivek P Chavda, Anjali Pandya, Sreeranjini Pulakkat, Moinuddin Soniwala, Vandana Patravale
As per the World Health Organization (WHO), ‘Lymphatic filariasis (LF) is a vector-borne neglected tropical disease that causes the damage of the lymphatic system and can lead to lymphoedema (elephantiasis) and hydrocele (excess fluid inside the human scrotal sac) in infected individuals’ [1]. The filarial parasites that cause this infection are carried by mosquitoes. Invasion from parasitic nematodes (roundworms or helminths) of the family Filariodidea, such as Wuchereria bancrofti (W.bancrofti), Brugia malayi (B.malayi), or Brugia timori, causes the disease [2,3]. LF affects the lymphatic system and can cause abnormal growth of bodily parts, resulting in discomfort, physical disability, and social stigma. More than 198 million people were infected globally in 2000, approximately 130 million people in 2014, while the 2018 projection of approximately 51 million infected people indicates the progress made thus far toward the eradication of LF as a public health burden due to implementation of chemotherapy in 2000 [4]. LF continues to endanger 859 million people in 50 countries all over the world, necessitating preventative treatment to halt the spread of such a parasitic disease. The annual benchmark estimation of LF patients suggests 25 million males having hydrocele and over 15 million persons with lymphedema. At least 40 million individuals continue to suffer from these chronic illness symptoms [5]. Preventing LF could help to reduce possible suffering and stigma among the vulnerable underprivileged population.
Related Knowledge Centers
- Anopheles
- Brugia Timori
- Drug Development
- Giemsa Stain
- Loa Loa
- Lymphangitis
- Lymphedema
- Wuchereria Bancrofti
- Lymphadenopathy
- Lymphatic Filariasis