Ocular pentastomiasis in the Democratic Republic of the Congo

Ocular Pentastomiasis in Human Hosts

This case report describes the pathogenesis of ocular pentastomiasis in human hosts.

Infectious eye disease in the 21st century-an overview

Infectious diseases affecting the eye often cause unilateral or asymmetric visual loss in children and people of working age. This group of conditions includes viral, bacterial, fungal and parasitic diseases, both common and rare presentations which, in aggregate, may account for a significant portion of the global visual burden. Diagnosis is frequently challenging even in specialist centres, and many disease presentations are highly regional. In an age of globalisation, an understanding of the various modes of transmission and the geographic distribution of infections can be instructive to clinicians. The impact of eye infections on global disability is currently not sufficiently captured in global prevalence studies on visual impairment and blindness, which focus on bilateral disease in the over-50s. Moreover, in many cases it is hard to differentiate between infectious and immune-mediated diseases. Since infectious eye diseases can be preventable and frequently affect younger people, we argue that in future prevalence studies they should be considered as a separate category, including estimates of disability-adjusted life years (DALY) as a measure of overall disease burden. Numbers of ocular infections are uniquely affected by outbreaks as well as endemic transmission, and their control frequently relies on collaborative partnerships that go well beyond the remit of ophthalmology, encompassing domains as various as vaccination, antibiotic development, individual healthcare, vector control, mass drug administration, food supplementation, environmental and food hygiene, epidemiological mapping, and many more. Moreover, the anticipated impacts of global warming, conflict, food poverty, urbanisation and environmental degradation are likely to magnify their importance. While remote telemedicine can be a useful aide in the diagnosis of these conditions in resource-poor areas, enhanced global reporting networks and artificial intelligence systems may ultimately be required for disease surveillance and monitoring.

Global status of neglected human Linguatula infection: a systematic review of published case reports

Human linguatulosis is a rare but highly specialized pentastomid parasitic infection all around the world. The disease is caused by worm-like parasites which share some morphologic features of arthropods and annelids. The life cycle of Linguatula spp. is provided as an example of pentastomid biology. The adult forms of Linguatula spp. are found in the nasal passages and frontal sinuses of dogs and other canids, domestic animals, and humans. Infestation may occur in the viscera, where immature forms develop in the liver, spleen, lungs, eyes, and other organs, or in the nasopharyngeal area. This review includes previous studies on the genus Linguatula in Iran and other countries from 1940 to 2019. Considering a few reports of human infestation, a comprehensive search was performed on both English and Persian databases for publications reporting human cases all around the world. Finally, 30 papers of 62 human cases were included in this study. The mean age of the patients was 25.8 years (varied from 8 to 79 years). Altogether, 41 (66.1%) and 21 (33.9%) of the patients were female and male respectively. The maximum cases (n = 25) were from Sudan. Nasopharynx was the most frequently involved organ in human cases. Our findings offer that physicians should consider the Linguatula infection in patients with complaints like unexpected dysphagia, with coughing, sneezing, and vomiting, after consuming raw/undercooked contaminated ruminant's viscera.

Detection of a Larva of Armillifer armillatus in a Potto (Perodicticus potto) from the Republic of the Congo

We determined the complete sequence of the mitochondrial DNA (mtDNA) of a parasite discovered between the subcutaneous tissue and the peritoneum of an African nocturnal non-human primate (NHP). The parasite and host sequences were obtained by a combination of Sanger sequencing and nanopore MinION techniques. Analyses of mtDNA gene arrangements and sequences unambiguously showed that the parasite investigated was the pentastomid Armillifer armillatus, also commonly named the tongue worm. The full-length mitochondrial genome of A. armillatus, measuring 16,706 bp in length, contains 13 protein-coding genes, 2 ribosomal RNA genes, and 22 transfer RNA genes, an arrangement identical to that of previously described pentastomid mitochondrial genomes. We describe here the second full mitochondrial genome of A. armillatus to date. To identify the NHP host, maximum likelihood phylogenetic analyses of a 441-bp fragment on the 12S rDNA gene and of a 1,140-bp fragment of the mitochondrial cytochrome b strongly support clustering with the African lorisid Perodicticus potto, a species that has rarely been reported as an intermediate host of this parasite.

Clinical manifestation and epidemiological findings of human linguatula serrate infection in Iran: systematic review

The aim of this study was to collect data and provide information on clinical diagnosis of disease, methods of dissemination, prevention and treatment of human linguatuliasis in order to increase people's awareness and health care. In this study case reports of individuals in Iran those infected with the Linguatula serrata were taken from the international databases (e.g., Medline (PubMed), Scopus, Iranmedex, Scientific Information Database, and Irandoc) and reviewed. The review covers the case reports of human tongue worm infection published either in Persian or in English between the years 1980-2018. An individual researcher undertook the bibliographic search and evaluation of articles based on inclusion/exclusion of specific criteria. Cases of infection have been reported in eight provinces of Iran. Dietary habits play the important roles in the transmission of the parasite. Clinical diagnosis was achieved by obtaining a patient's history, then completing a clinical examination of the mentioned patients. Symptoms of infection were mainly observed in the upper respiratory tract in most reports, the patient's status was improved by removing the parasite from the infected organ. Given that viscera of slaughtered livestock plays a significant role in the transmission of this infection to humans, Careful inspection of slaughtered livestock in slaughterhouses and Preventing the slaughter of livestock illegally and unsanitary, outside the slaughterhouse, is important. Accordingly, it is very important to train the employees working in the slaughterhouses and the people who consume these organs.

Armillifer Infections in Humans: A Systematic Review

Armillifer is a genus of obligate parasites belonging to the Pentastomida subclass that was first described as a cause of human disease in 1847. Human infection by Armillifer is rare and not widely known. These parasites are transmitted to humans by handling or eating undercooked meat from infected snakes, which are the definitive hosts, or oral uptake of environmental ova. The aim of this systematic review was to record all available evidence regarding infections by Armillifer in humans. A systematic review of PubMed (through 21 December 2018) for studies providing epidemiological, clinical, microbiological, as well as treatment data and outcomes of Armillifer infections was conducted. A total of 26 studies, containing data of 40 patients, were eventually included in the analysis. The most common sites of infection were the peritoneal cavity, the liver, the lower respiratory and the abdominal tract. The commonest infecting species was A. armillatus and most patients were asymptomatic; however, when symptoms occurred, the commonest was abdominal pain, even though unusual presentations occurred, such as hepatic encephalopathy or neurologic symptoms. Most cases were diagnosed at surgery or by imaging, and most patients were not treated. Mortality was low, but the majority of the cases with ocular infection lead to permanent loss of vision.

Linguatula serrata, a food-borne zoonotic parasite, in livestock in Bangladesh: Some pathologic and epidemiologic aspects

Food-borne parasitic zoonoses are major threats to human health and only next to the 'big three' such as AIDS, tuberculosis and malaria. Linguatula serrata is a food-borne zoonotic pentastomid that affects a wide range of animals including humans. Dogs and other carnivores are the final hosts while most herbivores, including domestic ruminants serve as intermediate hosts. Here, the study was conducted on some epidemiologic and pathologic aspects of L. serrata infection in cattle and goats through a slaughterhouse based survey. A total of 302 samples, consisting of 257 mesenteric, 26 hepatic and 19 pulmonary lymph nodes (LNs) of cattle and goats were collected. Out of 302 LNs, 136 (45.0%) were infected with the nymphal stage of L. serrata (50.7% of cattle and 31.0% of goats). Significantly, a higher (P = 0.002) rate of infection was detected in cattle. Sex, but not seasons, is a prominent determinant of the infection. The infection was mostly detected in the mesenteric LNs (MLNs) (50.9%) but the parasite was also detected in the hepatic (3.9%) and pulmonary (21.1%) LNs. Grossly, the affected LNs were enlarged, edematous and soft. Cut surface of the LNs showed spongy appearance, and sometimes nymphs were found to crawl out. Histopathological studies revealed severe damage in parenchyma of LNs, characterized by the loss of typical pattern of lymphatic follicles and trabecule. Massive infiltration with eosinophils was detected. Collectively, the data suggest that L. serrata infection is endemic in food animals and has significant pathological impacts on livestock, and people of the country are at high risk to linguatulosis.

Co-infections in Visceral Pentastomiasis, Democratic Republic of the Congo

Results of PCR and histology indicate this infection is endemic to this country.

Snakeborne Armillifer pentastomiasis is an emerging human parasitic infection in rural tropical areas where snake meat is eaten. After a series of severe ocular A. grandis larval infections and anecdotal abdominal infection in Sankuru District, Democratic Republic of the Congo, during 2014–2015, we systematically investigated possible pentastomid etiology in patients who underwent surgery in the region. Histologic and molecular analyses by established pentastomid 18S rDNA- and newly developed Armillifer-specific cytochrome oxidase PCRs revealed larval pentastomid lesions in 3.7% of patients. Some persons had A. armillatus and A. grandis co-infections. Another pentastomid larva, Raillietiella sp., was molecularly detected in 1 patient who had concomitant A. grandis and A. armillatus infection. The PCRs used were suitable for detecting pentastomid species even in highly necrotic tissues. Phylogenetic analyses of Armillifer cytochrome oxidase genes detected multiple local strains.

Armillifer-Infected Snakes Sold at Congolese Bushmeat Markets Represent an Emerging Zoonotic Threat

African pythons (Pythonidae) and large vipers (Bitis spp.) act as definitive hosts for Armillifer armillatus and Armillifer grandis parasites (Crustacea: Pentastomida) in the Congo Basin. Since the proportion of snakes in bushmeat gradually increases, human pentastomiasis is an emerging zoonotic disease. To substantiate the significance of this threat, we surveyed snakes offered for human consumption at bushmeat markets in the Kole district, Democratic Republic of the Congo, for the presence of adult pentastomids. In Bitis vipers (n = 40), Armillifer spp. infestations exhibited an 87.5% prevalence and 6.0 median intensity. Parasite abundance covaried positively with viper length, but not with body mass. In pythons (n = 13), Armillifer spp. exhibited a 92.3% prevalence and 3.5 median intensity. The positive correlations between parasite abundance and python length or mass were statistically nonsignificant. Ninety-one percent of A. grandis were discovered in vipers and 97% of infected vipers hosted A. grandis, whereas 81% of A. armillatus specimens were found in pythons and 63% of infected pythons hosted A. armillatus. Thus, challenging the widespread notion of strict host specificity, we found 'reversed' infections and even a case of coinfection. In this study, we also gathered information about the snake consumption habits of different tribal cultures in the area. Infective parasite ova likely transmit to humans directly by consumption of uncooked meat, or indirectly through contaminated hands, kitchen tools or washing water.

A Case of Pentastomiasis at the Left Maxilla Bone in a Patient with Thyroid Cancer

Pentastomiasis, a zoonotic parasite infection, is typically found in the respiratory tract and viscera of the host, including humans. Here, we report for the first time an extremely rare case of intraosseous pentastomiasis in the human maxilla suffering from medication related osteonecrosis of the jaw (MRONJ). A 55-year-old male had continuously visited the hospital for MRONJ which had primarily developed after bisphosphonate and anti-neoplastic administration for previous bone metastasis of medullary thyroid cancer. Pain, bone exposure, and pus discharge in the right mandible and left maxilla were seen. Osteolysis with maxillary cortical bone perforation at the left buccal vestibule, palate, nasal cavity, and maxillary sinus was observed by radiologic images. A biopsy was done at the left maxilla and through pathological evaluation, a parasite with features of pentastome was revealed within the necrotic bone tissue. Further history taking and laboratory evaluation was done. The parasite was suspected to be infected through maxillary open wounds caused by MRONJ. Awareness of intraosseous pentastomiasis should be emphasized not to be missed behind the MRONJ. Proper evaluation and interpretation for past medical history may lead to correct differential diagnosis and therapeutic intervention for parasite infections.

Molecular characterization and phylogeny of Linguatula serrata (Pentastomida: Linguatulidae) based on the nuclear 18S rDNA and mitochondrial cytochrome c oxidase I gene

Linguatula serrata, a cosmopolitan parasite, is commonly known as tongue worm belonging to the subclass Pentastomida.We collected the nymphal stage of the worm from mesenteric lymph nodes of cattle and identified these as L. serrata based on morphology and morphometry. The 18S rDNA sequences showed no intraspecific variation, although cox1 sequences showed 99.7–99.9% homology. In the phylogenies inferred from both gene loci, members of the genus Linguatula (order Porocephalida) were closer to those of the order Cephalobaenida than to those of Porocephalida, reflecting a mismatch with the corresponding morphology-based taxonomy. Accordingly, analyses of additional gene loci using a larger number of taxa across the Pentastomida should be undertaken to determine an accurate phylogenetic position within the Arthropoda.

Molecular Diagnosis of Abdominal Armillifer grandis Pentastomiasis in the Democratic Republic of Congo

Pentastomiasis is an emerging snake-borne parasitic zoonosis in the tropics. We describe a molecular and morphological study to diagnose a cluster of asymptomatic abdominal human infections caused by Armillifer grandis. The findings may indicate a silent epidemic in a rural area where severe symptomatic ocular cases with the same parasite species have recently surfaced. Molecular diagnostics are of increasing importance when patient material from remote areas cannot be thoroughly examined locally for logistic reasons.