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BMC Microbiology Jan 2024Filarial worms are important vector-borne pathogens of a large range of animal hosts, including humans, and are responsible for numerous debilitating neglected tropical...
BACKGROUND
Filarial worms are important vector-borne pathogens of a large range of animal hosts, including humans, and are responsible for numerous debilitating neglected tropical diseases such as, lymphatic filariasis caused by Wuchereria bancrofti and Brugia spp., as well as loiasis caused by Loa loa. Moreover, some emerging or difficult-to-eliminate filarioid pathogens are zoonotic using animals like canines as reservoir hosts, for example Dirofilaria sp. 'hongkongensis'. Diagnosis of filariasis through commonly available methods, like microscopy, can be challenging as microfilaremia may wane below the limit of detection. In contrast, conventional PCR methods are more sensitive and specific but may show limited ability to detect coinfections as well as emerging and/or novel pathogens. Use of deep-sequencing technologies obviate these challenges, providing sensitive detection of entire parasite communities, whilst also being better suited for the characterisation of rare or novel pathogens. Therefore, we developed a novel long-read metabarcoding assay for deep-sequencing the filarial nematode cytochrome c oxidase subunit I gene on Oxford Nanopore Technologies' (ONT) MinION™ sequencer. We assessed the overall performance of our assay using kappa statistics to compare it to commonly used diagnostic methods for filarial worm detection, such as conventional PCR (cPCR) with Sanger sequencing and the microscopy-based modified Knott's test (MKT).
RESULTS
We confirmed our metabarcoding assay can characterise filarial parasites from a diverse range of genera, including, Breinlia, Brugia, Cercopithifilaria, Dipetalonema, Dirofilaria, Onchocerca, Setaria, Stephanofilaria and Wuchereria. We demonstrated proof-of-concept for this assay by using blood samples from Sri Lankan dogs, whereby we identified infections with the filarioids Acanthocheilonema reconditum, Brugia sp. Sri Lanka genotype and zoonotic Dirofilaria sp. 'hongkongensis'. When compared to traditionally used diagnostics, such as the MKT and cPCR with Sanger sequencing, we identified an additional filarioid species and over 15% more mono- and coinfections.
CONCLUSIONS
Our developed metabarcoding assay may show broad applicability for the metabarcoding and diagnosis of the full spectrum of filarioids from a wide range of animal hosts, including mammals and vectors, whilst the utilisation of ONT' small and portable MinION™ means that such methods could be deployed for field use.
Topics: Humans; Animals; Dogs; Coinfection; Filarioidea; Filariasis; Brugia; Wuchereria bancrofti; Mammals
PubMed: 38245715
DOI: 10.1186/s12866-023-03159-3 -
BMC Veterinary Research Jan 2024Camel filariasis induced variable clinical syndromes characterized by fever, lethargy, localized dermal lesions, loss of condition, and testicular and scrotal swelling....
Camel filariasis (Dipetalonema evansi) and its association with clinical balanoposthitis with reference to prominent changes in clinical findings, serum testosterone, semen analysis, and testicular histopathology.
BACKGROUND
Camel filariasis induced variable clinical syndromes characterized by fever, lethargy, localized dermal lesions, loss of condition, and testicular and scrotal swelling. The objective of the present work focused on clarifying the diagnostic importance of clinical findings, serum testosterone, and semen analysis as well as blood smear and testicular histopathology as a differential tool between only balanoposthitis without filariasis male camels group (OnlyBp) and balanoposthitis-filariasis infected male camels group (BpFl). The study also monitored the associations between the severity of ticks' infestations in investigated male camels and the occurrence of balanoposthitis only or balanoposthitis with filariasis.
RESULTS AND CONCLUSIONS
The study reported significant correlation between serum testosterone, serum cortisol, and sperm vitality and abnormalities percentages. The study included male camels (n = 250) classified into three groups: healthy control group (Cont; n = 30), OnlyBp (n = 210), and BpFl (n = 10). These male camels were clinically and laboratory examined, and skin scraping tests and testicular histopathology were conducted. The study confirmed the association of the changes in clinical findings, whole blood picture, serum testosterone, serum cortisol, and semen analysis, with OnlyBp and BpFl. These changes were more prominent in BpFl than in OnlyBp. Skin scraping test results revealed a higher severity of live ticks' infestation in BpFl than in OnlyBp because, unlike OnlyBp, all camels in BpFl (n = 10) were suffering from live ticks' infestation. It also concluded the higher efficacy of histopathology of testicular tissues in male camels as a diagnostic tool for adult filaria in balanoposthitis-affected male camels than blood smear because all cases of camel filariasis in the current work were negative for microfilaria on microscopic examination of diurnal blood smear as well as testicular histopathology revealed detection of adult filaria in all camel filariasis associated with balanoposthitis. Strong correlation relationships were demonstrated between serum testosterone, serum cortisol, and semen analysis results. Positive correlations were reported between serum testosterone levels and sperm vitality percentages. However, negative correlations were stated between serum testosterone and each of serum cortisol and sperm abnormalities either in Cont, OnlyBp or BpFl.
Topics: Male; Animals; Camelus; Dipetalonema; Semen; Hydrocortisone; Semen Analysis; Filariasis; Nematode Infections; Testosterone
PubMed: 38172872
DOI: 10.1186/s12917-023-03844-5 -
Parasite (Paris, France) 2023Filarial nematodes of the Dipetalonema lineage are widespread parasites and include some species that are transmitted by ticks. In this study, we conducted a large...
Filarial nematodes of the Dipetalonema lineage are widespread parasites and include some species that are transmitted by ticks. In this study, we conducted a large molecular survey of ticks in French Guiana, South America, to understand the overall diversity of tick-borne filarioids in this remote region largely covered by dense tropical forests. Out of 682 ticks belonging to 22 species and 6 genera, 21 ticks (3.1%) of the species Amblyomma cajennense, A. oblongoguttatum, A. romitii, Ixodes luciae and Rhipicephalus sanguineus sensu lato were positive for infection by filarioids. Molecular typing and phylogenetic analysis identified all these filarioids as members of the Dipetalonema lineage. While the filarioid of R. sanguineus sensu lato is a previously described species, the canine worm Cercopithifilaria bainae Almeida & Vicente, 1984, all other filarioids detected in this study are related but distinct to already known species in the genera Cercopithifilaria, Cruorifilaria and Dipetalonema. Their vertebrate host range may include a wide variety of mammals present in French Guiana, but dogs, capybaras, and opossums are the best candidate hosts for some of these filarioids. Although the detection of members of the Dipetalonema lineage in ticks of significant medical or veterinary interest is of concern, the risk of contracting a tick-borne filarial infection is still largely unknown. The pathogenicity of these filarioids, their epidemiology, developmental cycles, and mechanisms of transmission by South American tick species now require further study.
Topics: Animals; Dogs; Dipetalonema; French Guiana; Phylogeny; Dog Diseases; Filarioidea; Ixodes; Tick-Borne Diseases; Mammals
PubMed: 37404115
DOI: 10.1051/parasite/2023027 -
Parasitology Research Sep 2023Among vector-borne helminths, filarioids of the genus Dipetalonema (Spirurida: Onchocercidae) localize in several tissues and body cavities of several animal species,...
Among vector-borne helminths, filarioids of the genus Dipetalonema (Spirurida: Onchocercidae) localize in several tissues and body cavities of several animal species, causing mild to moderate lesions. The pathological findings associated with Dipetalonema spp. infection in Neotropical monkeys from southern Brazil are herein described, along with a fatal case due to filarial polyserositis and entrapment of an intestinal segment. At necropsy, nematodes were observed in abdominal and thoracic cavities, or in the pericardium of 37 (31.3%) out of the 118 individuals examined (i.e., 35 Alouatta guariba clamitans and two Sapajus nigritus). In addition, at histology, 27.0% of positive animals presented microfilarie (inside blood vessels of lung, spleen, liver, and brain) and 8.1% presented adult nematodes in the heart, lung, and liver. In two cases, cross-sections of filarioids were associated with areas of epicardial thickening with intense fibrosis and pyogranulomatous inflammation in the brain, heart, liver, lungs, or spleen. The DNA fragment was amplify using the cox1 gene, sequenced and analyzed to identify the nematode species collected; presence of Wolbachia was assessed in the filarioids using the 16S rRNA gene. At BLAST analysis of the cox1 gene, 10 sequences showed 91.7% nucleotide identity with Dipetalonema gracile, and two with D. gracile (98.5%) and Dipetalonema graciliformis (98.3%). Phylogenetic analyses clustered sequences of the cox1 obtained in this study in two clades corresponding with the host species. Wolbachia sp. endosymbiont was detected in four samples. Data herein reported provide a description of pathological lesions associated with the infection by Dipetalonema spp., suggesting that they may cause disease in Neotropical monkeys. In addition, a better understanding of diversity and biology of Dipetalonema spp. in South America is needed to assess the impact they may cause in native non-human primates from Brazil.
Topics: Animals; Dipetalonema; Spirurida; Brazil; Haplorhini; Phylogeny; RNA, Ribosomal, 16S; Filarioidea; Dipetalonema Infections; Nematoda
PubMed: 37347285
DOI: 10.1007/s00436-023-07895-3 -
Acta Tropica Nov 2022Filarial nematode infections are common in primates, but have received little attention in the Neotropics. Epidemiological data on filarial infections in primates are...
Filarial nematode infections are common in primates, but have received little attention in the Neotropics. Epidemiological data on filarial infections in primates are still too sparse to fully understand the complex of this parasitism, especially because of the difficulty in studying the ecology and epidemiology of wild primates.. We describe natural infections by Dipetalonema parasitizing 211 primates belonging to eight free-living primate genera in Amazonia, and assess the relationships between parasitic indicators and climatic (rainfall and river level), ecological (fruiting periods of plants) and biological (sex, species' body mass, group size and density) factors. The overall prevalence was 64.4% (95% CI: 64.0 - 64.9); parasitic mean abundance (N filariae per individual) and parasitic mean intensity (N filariae per infected host) of infection were 11.9 (95% CI: 8.3 - 15.6) and 18.4 (95% CI: 13.4 - 23.4) filariae/individual, respectively. Although we observed differences in parasitic parameters among primate genera, there was no correlation between parasitic parameters with density, body mass or group size. Sapajus, Cebus and Lagothrix had the highest prevalence and parasitic mean intensity. Using Lagothrix lagotricha poeppigii, the most sampled species (n = 92), as a model, we found that the number of filariae per infected host was associated with fruit production in swamp forests during the dry season, the time of food scarcity. The long periods of food shortage may cause environmental stress on primates, impairing their immune defenses and leading to increased parasite load but not affecting infection prevalence. However, the lack of information on vector ecology, key to understand risk factors associated to infection rate, prevents confirming the existence of an infection pattern dependent on food availability.
Topics: Animals; Brazil; Forests; Fruit; Seasons
PubMed: 36037980
DOI: 10.1016/j.actatropica.2022.106670 -
Journal of Parasitic Diseases :... Dec 2021Camels are important sources of milk, meat, wool and leather, and are widely used in transportation in arid and semi-arid areas. But their illnesses, especially...
Camels are important sources of milk, meat, wool and leather, and are widely used in transportation in arid and semi-arid areas. But their illnesses, especially parasitic diseases, have not been taken into consideration. The microfilariae are in the blood. Adult nematode is only dedicated to camels and disrupts spermatic arteries, lung arteries, right atrium, and testicles. This study was carried out on testicular samples of camels infected with referred from slaughterhouse. In each of the control and contaminated groups, 5 samples were examined. In this study, in addition to the qualitative description of parasite histopathologic lesions, the spermatogenesis process was evaluated quantitatively including spermatogenesis process, diameter of the seminiferous tubules and Johnsen ranking and compared with the control group. Histopathological examination of infected testis with showed lumen obstruction of testicular blood vessels by parasites, hypertrophy of blood vessels, degenerative and necrosis changes in the tubules, decreased spermatogenetic activity, increased interstitial space tubules, destruction of the spermatogenic cells. Also, there was a significant difference in the control and contaminated groups in the parameters of spermatogenesis, diameter of the seminiferous tubules and Johnsen score.
PubMed: 34789978
DOI: 10.1007/s12639-021-01384-z -
Parasitology Sep 2021Six Dipetalonema species have been reported from Neotropical monkeys, Dipetalonema gracile, Dipetalonema graciliformis and Dipetalonema caudispina being the dominant...
Six Dipetalonema species have been reported from Neotropical monkeys, Dipetalonema gracile, Dipetalonema graciliformis and Dipetalonema caudispina being the dominant species found in French Guiana primates. Adult filarioids isolated from the abdominal cavity of tamarins (Saguinus midas) in French Guiana were morphologically and molecularly identified as D. graciliformis. Phylogenetic analysis based on DNA and amino acid sequences of the cox1 gene as well as the concatenated sequences of the cox1 and the 18S genes indicated that D. graciliformis belongs to the clade 4 (ONC4) of Onchocercidae. Blast analysis of the 18S rDNA revealed that D. graciliformis in the studied tamarins is conspecific with the filarioid circulating in howler monkeys (Alouatta macconnelli) in French Guiana, previously referred to as unidentified Onchocercidae species.
Topics: Animals; Dipetalonema; Dipetalonema Infections; Female; French Guiana; Male; Monkey Diseases; Saguinus
PubMed: 34100346
DOI: 10.1017/S0031182021000901 -
Parasites & Vectors Oct 2020Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the...
BACKGROUND
Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott's test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides).
RESULTS
A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott's tests one month after the last treatment.
CONCLUSIONS
We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.
Topics: Acanthocheilonema; Acanthocheilonemiasis; Animals; Antigens, Helminth; Blood; Dirofilaria immitis; Dirofilariasis; Dog Diseases; Dogs; False Positive Reactions; Female; Hot Temperature; Immunologic Tests; Microfilariae
PubMed: 33004047
DOI: 10.1186/s13071-020-04376-9 -
Pathogens (Basel, Switzerland) Jul 2020Previous studies have reported filarial parasites of the genus and from French Guiana monkeys, based on morphological taxonomy. In this study, we screened blood...
Previous studies have reported filarial parasites of the genus and from French Guiana monkeys, based on morphological taxonomy. In this study, we screened blood samples from nine howler monkeys () for the presence of filaria and DNA. The infection rates were 88.9% for filaria and 55.6% for wolbachiae. The molecular characterization, based on the gene of filariids, revealed that are infected with at least three species ( sp., sp. and an unidentified Onchocercidae species.). Since the and generic primers are not very effective at resolving co-infections, we developed ITS genus-specific PCRs for and genus. The results revealed coinfections in 75% of positives. The presence of sp. and sp. was also confirmed by the phylogenetic analysis of their associated . sp., which close to the species from the subgenus encountered in New World Monkeys, while sp. was identical to the strain circulating in French Guiana dogs. We propose a novel genus-specific qPCR. We applied it to screen for infection in howler monkeys and 66.7% were found to be positive. Our finding highlights the need for further studies to clarify the species diversity of neotropics monkeys by combining molecular and morphological features. The novel genus-specific qPCR assays could be an effective tool for the surveillance and characterization of this potential zoonosis.
PubMed: 32752052
DOI: 10.3390/pathogens9080626 -
Journal of Parasitic Diseases :... Dec 2019The prevalence and species spectrum of some blood and intestinal parasites affecting imported camels was studied on a total of 120 clinically suspected camels (males)...
The prevalence and species spectrum of some blood and intestinal parasites affecting imported camels was studied on a total of 120 clinically suspected camels (males) imported to Egypt from Sudan during the period from January till July 2016 in Abu-Simbel quarantine station, Aswan governorate. Blood and fecal samples were collected from all camels under the study. The fecal samples were collected and examined by sedimentation-floatation techniques for detection of parasitic eggs/oocysts. Coprological examination revealed that the prevalence rate of the parasitic infection was 60% (72 out of 120). Eighteen species of helminthes/protozoan parasites eggs/oocysts were encountered stongyles species were the hightest prevalent of nematodes 12.5%. Four genera of flat worms were identified in the present study including sp. 0.8%, sp. 3.3%, sp. 7.5% and sp. 0.8%. Four species of were identified (, , and ) in infected camels the commenst one is 15.8%, sp. and were recorded with a prevalence rate about 15.8%, 8.3% and 6.7% respectively. Blood smears from jugular vein revealed that 2.5% of camels were infected with Wide spectrum and high prevalence of internal parasites were observed in the present study which may be lead to severe economic losses, so the application of control measures and treatment of infected camels with specific and effective drugs during the quarantine period are most important to prevent spreading of parasitic infestation and/or introduction of parasites previously not exist in our country.
PubMed: 31749532
DOI: 10.1007/s12639-019-01138-y