Comparison of capillary, venous and buffy coat blood samples in detecting Plasmodium species among malaria suspected patients attending at Hamusite health center. A cross-sectional study.

BACKGROUND: Both capillary and venous blood samples have been interchangeably used for the diagnosis of malaria in Ethiopia. However, Plasmodium parasites are thought to be more concentrated in capillary than in venous blood. Hence, selecting a sample source where parasites are more concentrated is indispensable approach in order to maximize the accuracy of blood film microscopy. Therefore, the present study aimed to compare the detection rate and the parasitemia level of Plasmodium species from conventional capillary and venous blood films, and buffy coat preparations. METHODS: A facility based cross-sectional study was conducted from Feburary to March 2020 among 210 febrile patients attending Hamusite health center, northwest Ethiopia. Capillary and venous blood samples were collected and buffy coat was prepared from each sample. Thin and thick blood films were prepared, stained, and examined microscopically following standard protocol. Data were analysed using Statistical Package for Social Sciences Software version 20 and Med-Calc software version 19.3. RESULTS: Capillary blood buffy coat (61/210, 29.0%) had significantly higher detection rate as compared to capillary (48/210, 22.9%) and venous (42/210, 20.0%) blood films (p < 0.001). However, no significant difference was observed between capillary and venous blood films (p = 0.070) in detecting Plasmodium species. The highest and the lowest mean asexual stage parasite counts were found in capillary blood buffy coat (4692.88) and venous blood (631.43) films, respectively showing significant variations (p < 0.001). Mean gametocyte count was also highest in capillary blood buffy coat (3958.44). As compared to capillary blood buffy coat, the sensitivity of venous blood buffy coat, capillary blood film and venous blood film were 73.8, 78.7, 68.9%, respectively. CONCLUSION: Capillary blood buffy coat samples showed the highest sensitivity in detecting and quantitating malaria parasites that its use should be promoted in clinical settings. However, conventional capillary and venous blood films could be used interchangeably.

Comparison of capillary and venous blood for malaria detection using two PCR-based assays in febrile patients in Sierra Leone.

BACKGROUND: Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive. METHODS: Paired clinical samples of venous and capillary blood from 141 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay. RESULTS: No significant differences in Plasmodium parasite detection between capillary and venous blood for both assays were observed. The GFP assay was more sensitive than MMSR for all markers that could be compared (Plasmodium spp. and Plasmodium falciparum) in both venous and capillary blood. CONCLUSIONS: No difference was found in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data gives support for use of capillary blood, a material which can be obtained easier by less invasive methods, for PCR-based malaria diagnostics, independent of the platform.

Comparison on simultaneous caillary and venous parasite density and genotyping results from children and adults with uncomplicated malaria: a prospective observational study in Uganda.

BACKGROUND: Blood smear microscopy remains the gold-standard method to diagnose and quantify malaria parasite density. In addition, parasite genotyping of select loci is the most utilized method for distinguishing recrudescent and new infections and to determine the number of strains per sample. In research settings, blood may be obtained from capillary or venous compartments, and results from these matrices have been used interchangeably. Our aim was to compare quantitative results for parasite density and strain complexity from both compartments. METHODS: In a prospective observational study, children and adults presenting with uncomplicated Plasmodium falciparum malaria, simultaneous capillary and venous blood smears and dried blood spots were collected over 42-days following treatment with artemether-lumefantrine. Blood smears were read by two microscopists, any discrepancies resolved by a third reader. Parasite DNA fingerprinting was conducted using six microsatellites. Bland Altman analysis and paired t-test/McNemar's test were used to assess the difference in density readings and measurements. RESULTS: Two hundred twenty-three participants were included in the analysis (177 children (35 HIV-infected/142 HIV-uninfected), 21 HIV-uninfected pregnant women, and 25 HIV-uninfected non-pregnant adults). Parasite density measurements did not statistically differ between capillary and venous blood smears at the time of presentation, nor over the course of 42-day follow-up. Characterization of merozoite surface protein-2 (MSP-2) genetic polymorphism demonstrated a higher level of strain diversity at the time of presentation in venous samples, as compared with capillary specimens (p = 0.02). There was a high degree of variability in genotype-corrected outcomes when pairs of samples from each compartment were compared using MSP-2 alone, although the variability was reduced with the use of multiple markers. CONCLUSIONS: Parasite density measurements do not statistically differ between capillary and venous compartments in all studied demographic groups at the time of presentation with malaria, or over the course of follow-up. More strains were detected by MSP-2 genotyping in venous samples than in capillary samples at the time of malaria diagnosis. The use of multiple polymorphic markers reduces the impact of variability in strain detection on genotype-corrected outcomes. This study confirms that both capillary and venous compartments can be used for sampling with confidence in the clinical research setting. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov under registration no. NCT01717885 .

Peripheral venous vs. capillary microfilariaemia in a dog co-infected with Dirofilaria repens and D. immitis: A comparative approach using triatomine bugs for blood collection.

Dirofilaria immitis and D. repens are mosquito-borne nematodes, primarily infecting dogs, but also other species of carnivores and even humans. Given their impact on animal and human health, the transmission of these filarioids has been widely studied. The microfilariaemia has been shown to have a circadian variation for both Dirofilaria species infecting dogs. Due to methodological difficulties, the periodicity was only studied using venous blood samples, while the mosquitoes feed, in fact, on capillary blood. In this context, the present study aimed to test the feasibility of using triatomine bugs for the collection of capillary blood and to comparatively evaluate the level of microfilariaemia and its circadian variation in capillary blood vs. peripheral venous blood in a dog naturally co-infected with D. immitis and D. repens. The results showed a feeding success of 50%, with variations in the blood meal volume that the bugs ingested. The relative values of microfilariaemia (mf/bug) were strongly correlated with the volume of blood recovered: the more blood recovered from each bug, the higher values of microfilariaemia in the evening samples while the opposite results were obtained for the morning samples. The counting of microfilariae revealed a dominance of D. immitis in all the samples, but with significantly higher microfilariaemia in the venous blood. Meanwhile, for D. repens, the situation was opposite, with higher counts in the capillary blood samples. Our study showed that triatomine bugs can be used as a model for the collection and study of microfilariaemia in the capillary blood in mammals.

Do the venous blood samples replicate malaria parasite densities found in capillary blood? A field study performed in naturally-infected asymptomatic children in Cameroon.

BACKGROUND: The measure of new drug- or vaccine-based approaches for malaria control is based on direct membrane feeding assays (DMFAs) where gametocyte-infected blood samples are offered to mosquitoes through an artificial feeder system. Gametocyte donors are identified by the microscopic detection and quantification of malaria blood stages on blood films prepared using either capillary or venous blood. However, parasites are known to sequester in the microvasculature and this phenomenon may alter accurate detection of parasites in blood films. The blood source may then impact the success of mosquito feeding experiments and investigations are needed for the implementation of DMFAs under natural conditions. METHODS: Thick blood smears were prepared from blood obtained from asymptomatic children attending primary schools in the vicinity of Mfou (Cameroon) over four transmission seasons. Parasite densities were determined microscopically from capillary and venous blood for 137 naturally-infected gametocyte carriers. The effect of the blood source on gametocyte and asexual stage densities was then assessed by fitting cumulative link mixed models (CLMM). DMFAs were performed to compare the infectiousness of gametocytes from the different blood sources to mosquitoes. RESULTS: Prevalence of Plasmodium falciparum asexual stages among asymptomatic children aged from 4 to 15 years was 51.8% (2116/4087). The overall prevalence of P. falciparum gametocyte carriage was 8.9% and varied from one school to another. No difference in the density of gametocyte and asexual stages was found between capillary and venous blood. Attempts to perform DMFAs with capillary blood failed. CONCLUSIONS: Plasmodium falciparum malaria parasite densities do not differ between capillary and venous blood in asymptomatic subjects for both gametocyte and trophozoite stages. This finding suggests that the blood source should not interfere with transmission efficiency in DMFAs.

First detection of Allobilharzia visceralis (Schistosomatidae, Trematoda) from Cygnus cygnus in Japan.

Adult schistosomes were detected in the veins or capillaries of the large intestine, mesentery, liver, and adrenal glands in eight of 13 whooper swans (Cygnus cygnus) examined in Iwate Prefecture, Japan. However, neither eggs nor severe tissue injuries were observed in any of the swans. The schistosomes were definitively identified as Allobilharzia visceralis based on the nucleotide sequences of the ribosomal internal transcribed spacer (ITS) region. Allobilharzia visceralis infections have been reported in whooper swan in Iceland and tundra swan (Cygnus columbianus) in North America. These detections suggest that A. visceralis is distributed extensively along the swan flyways because the swans are migratory birds. To the best of our knowledge, this is the first report of A. visceralis infection in Asia.

Histopathology associated with angiostrongylosis in Akodon species (Rodentia: Sigmodontinae) from Sierra de la Ventana, Buenos Aires, Argentina.

Angiostrongylus is a metastrongylid nematode genus that includes species found in carnivores, rodents, and occasionally primates (including humans). About 100 species of wild sigmodontine rodents occur in Argentina, 16 of which are species of Akodon. The lungs of Akodon azarae and Akodon dolores from Sierra de la Ventana, Buenos Aires, Argentina, were examined, and 2 of 10 A. dolores specimens were positive for angiostrongylosis, showing macroscopic lesions of verminous pneumonia. Adults found were identified as Angiostrongylus morerai. Histopathology of the lungs revealed multiple nodules in the interstitium, alveoli, and vessels, resulting in interstitial fibrosis and the destruction of small capillaries and arterioles. Since extensive pathology in the lung was noted here from only 2 adults, it is probable that heavier infections may cause mortality in their hosts. This is the first record of this nematode species from A. dolores , expanding its geographic distribution to the southwest of Buenos Aires Province, and the first description of the histopathology of larval angiostrongylosis in a wild rodent from South America.

Navigation within host tissues: cues for orientation of Diplostomum spathaceum (Trematoda) in fish towards veins, head and eye.

Cercariae of Diplostomum spathaceum penetrate the skin of fish, and then migrate along blood vessels and tissues towards the head and the eye-lens. We studied their orientation behaviour in tail fins of guppies and in chemical concentration gradients within agar-filled choice chambers. In fins, they entered veins and orientated cranially, independent of the blood flow and living cells. In choice chambers, they were attracted by a small molecular fraction of fish serum, D-glucose (at 1, 10, and 1000 microM), D-mannose, D-maltotriose and Cl-ions, whereas D-glucosamine repelled them (even at 1.0 nM). Amino acids were not attractive, but arginine in tetrapeptides attracted at concentrations as low as 1 microm and melatonin at 0.4-4.3 PM. We suggest a preliminary model for the behaviour of diplostomula in fish fins and attracting (+) or repelling (-) host cues: (1) migration towards deeper skin layers and avoidance of skin surface, cues: Cl-ions (+ and -), glucose (+), glucosamine (-), light radiation (-); (2) orientation in cranial direction, cue: Cl-ions (+); (3) localization of blood vessels, cues: glucose (+), arginine-residues (+); (4) localization of the retina, cue: melatonin (+). A comparison with the navigation mechanisms of tissue-migrating schistosomules and hookworm larvae reveals an enormous diversity of strategies.

O plexo pampiniforme na fase crônica da doença de Chagas humana: avaliaçäo histológica / The pampiniform plexus of chronic chagasic patients: a histologic evaluation

Pesquisou-se a ocorrência, na parede das veias do plexo pampiniforme de chagásicos crônicos, de acúmulos intracelulares de Trypanosoma cruzi e sinais inflamatórios (flebife). Para tal fim, colheram-se, à necropsia, 23 pares de funículos espermáticos, epidídimos e testículos, sendo 17 de chagásicos crônicos e 6 de controles (näo chagásicos). Em cada caso, foram feitos múltiplos cortes das gônadas e dos vasos; fez-se pesquisa de T. cruzi por imuno-histoquímica nos funículos espermáticos de todos os casos. Näo se observaram parasitos nas paredes vasculares. Notou-se flebite crônica inespecífica, focal e discreta, em cinco chagásicos (bilateral em três pacientes) e dois controles; havia infiltraçäo mononuclear discreta do interstício funicular em treze chagásicos e cinco controles. A análise estatística dos resultados (X²) näo revelou diferenças significativas. Conclui-se que o ambiente hormonal devido à testosterona näo parece favorecer a infecçäo da parede dos vasos gonadais por Trypanosoma cruzi, embora, segundo a literatura, o referido hormônio pareça ter açöes imunodepressoras

Evolution of the schistosomes (Digenea: Schistosomatoidea): the origin of dioecy and colonization of the venous system.

Trematodes of the family Schistosomatidae are considered venous system specialists whose sister group is the vascular system generalists (Spirorchidae) of turtles. Colonization of homeotherms by vascular trematodes required precision egg laying near the conduit for egg passage to the external environment and avoidance of pathogenesis that might result in the premature death of the host. Evolution of dioecy from the hermaphroditic condition may have proceeded through androdioecy in which hermaphrodites were specialized for precision egg placement in the vascular system and larger adults became functional males. The evolution of nuclear genes suppressing female function along with cytoplasmic genes suppressing male function could then have resulted in the origin of dioecious, dimorphic populations. Schistosomes compensated for the reduction in potential reproductive partners by (1) increased overdispersion in the vertebrate host, (2) reduced egg hatching time in the external environment, (3) formation of permanent pairs mimicking the hermaphroditic condition, (4) increased longevity in the definitive host, and (5) increased fecundity. Colonization of the venous system was necessitated by (1) evolutionary radiation into terrestrial vertebrates and (2) the increased immunopathology associated with the high, constant body temperature of homeothermic vertebrates. The immune response to spirorchid and schistosome eggs appears to be qualitatively similar in their respective hosts. The arterial dwelling spirorchids release eggs in the direction of blood flow, resulting in a wide dissemination of eggs within the host. The lower body temperature of poikilotherms accompanied by the seasonal nature of the immune response in these hosts would result in a quantitatively reduced pathogenesis. Hosts that did succumb to the infection would most likely die in water, where eggs could be released by predation, scavengers, or decomposition and develop successfully. Colonization of the venous system by schistosomes would require precision egg placement because eggs are released against blood flow. Eggs are sequestered within the portal system of homeotherms, thus restricting egg dispersal and resulting pathogenesis to less sensitive organs. A significant number of eggs may escape into the external environment before a heavily infected host is incapacitated by, or dies from, the infection.

Correlation between adrenal central vein parasitism and heart fibrosis in chronic chagasic myocarditis.

The correlation between Trypanosoma cruzi parasitism of the adrenal central vein (ACV) wall and fibrous connective tissue neoformation in the left ventricular myocardium (LVM) of patients with chronic Chagas' disease who were autopsied was evaluated using the following procedures: 1) a comparison of the incidence of fibrosis in the LVM among 18 chagasic patients with ACV parasitism and 18 individuals without phleboparasitism; 2) a determination of fibrosis intensity in the LVM in 12 cases with ACV parasites and in 12 cases without phleboparasitism, matched with respect to age, sex, race, and anatomoclinical form of the disease (indeterminant, cardiac, and digestive forms); and 3) in the cases with ACV parasitism, a calculation of Pearson's correlation coefficient between T. cruzi nests in the vessel and the intensity of fibrous connective tissue neoformation in the LVM. Among chagasic individuals with adrenal phleboparasitism, there was an increased incidence and intensity of fibrous connective tissue neoformation in the LVM, both highly significant, compared with patients without adrenal phleboparasitism. Furthermore, there was a positive, though nonsignificant, correlation (r = +0.19) between the density of nests in the ACV and the intensity of myocardial fibrosis. These results are consistent with previous data showing a higher intensity of the leukocyte exudate in the LVM and increased heart weight in individuals with T. cruzi nests in the ACV, suggesting a role of parasitism at that site in terms of the development of chronic chagasic cardiopathy.

[Cardiac weight in patients with chronic Chagas disease with Trypanosoma cruzi nests in the central vein of the adrenal glands]. / Peso cardíaco em chagásicos crônicos com ninhos de Trypanosoma cruzi na veia central da supra-renal.

PURPOSE: Comparative analysis of cardiac weight (CW) in patients with chronic Chagas disease, with or without parasitism by Trypanosoma cruzi in the central vein of the adrenal gland (CVAG). METHODS: The CW has been studied in 96 necropsied individuals with chronic Chagas disease. Among them, 48 of them had Trypanosoma cruzi nests on the wall of the CVAG and the other 48 patients did not have nests in the CVAG. Later, this sample was paired for sex, age and anatomo-clinical form, resulting in 60 patients. Among these patients, 30 of them had Trypanosoma cruzi nests on the walls of the CVAG and the other 30 did not have. RESULTS: The CW of Chagas patients which had nests of T. cruzi in the CVAG, was 484.8 +/- 146.0g, while in the ones that did not have the nests on the walls of the CVAG, the CW weight was 415.8 +/- 125.3g. This difference was statistically significant. In the first group it had a prevail of congestive heart failure. Subsequently to the pairing for sex, age and anatomo-clinical form, the CW was respectively 464.3 +/- 146.2g and 436.0 +/- 108.9g. This difference was not statistically significant. CONCLUSION: These data suggest that the parasitism in the central vein of the adrenal gland, combined with other possible events intrinsic to the chronic Chagas disease patients' hearts, carries a supporting role in the increasing of the cardiac weight and in the congestive cardiac insufficiency.

Cattle schistosomiasis in Zambia.

A total of 358 cattle was examined for schistosome infection in Zambian slaughterhouses. A total of 542 worms collected from 104 infected individuals was examined for glucose-6-phosphate dehydrogenase and phosphoglucomutase using isoelectric focusing. The overall prevalence of infection was 51%. Ninety three percent of the infected animals had less than 100 worm pairs in the mesenteric veins. Schistosoma mattheei was the predominant species (75%); S. leiperi (12%) and S. margrebowiei (2%) were also identified. The remaining 11% of the worms showed one of two distinct heterozygote patterns. Pattern A is identical to that of a laboratory-produced F1 S. mattheei x S. haematobium hybrid, but could also represent a S. mattheei x S. leiperi hybrid. Further studies are required to elucidate the origins of pattern B.

Reaçäo de fase aguda e parasitismo na veia central da supra-renal de chagásicos crônicos / Acute-phase reaction and parasitism in the central adrenal vein in Chagas' disease patients

The systemic reaction to severe trauma and/or infection, acute phase response (APR), are often associated with immunosuppression and reactivation of chronic latent infection. Our main purpose was to verify, in a group of 71 autopsied chronic chagasic with or without APR, the frequency of T. cruzi nests in the central vein of adrenal gland (CVAG). APR, defined by: 1) death secondary to sepsis and/or trauma plus, 2) bleeding stress gastric ulcerations or 3) spleen reactional state or 4) liver steatosis, was observed in 30 chronic chagasic (APR+). Weight, height and body mass index (BMI) were obtained. APR(+) chronic chagasic had worse nutritional status than APR(-) ones: weight = 49.0 vs 54.5 kg; BMI = 17.5 vs 20.6 kg/m2 (median p < 0.05). CVAG T. cruzi nests frequency were similar (43.3 per cent and 43.9 per cent , respectively) between both Groups. We conclude that APR(+) chronic chagasic had worse nutritional status than APR(-) ones, and that APR development did not change the CVAG T. cruzi nests frequency

[Acute-phase reaction and parasitism in the central adrenal vein in Chagas' disease patients]. / Reação de fase aguda e parasitismo na veia central da supra-renal de chagásicos crônicos.

The systemic reaction to severe trauma and/or infection, acute phase response (APR), are often associated with immunosuppression and reactivation of chronic latent infection. Our main purpose was to verify, in a group of 71 autopsied chronic chagasic with or without APR, the frequency of T. cruzi nests in the central vein of adrenal gland (CVAG). APR, defined by: 1) death secondary to sepsis and/or trauma plus, 2) bleeding stress gastric ulcerations or 3) spleen reactional state or 4) liver steatosis, was observed in 30 chronic chagasic (APR+). Weight, height and body mass index (BMI) were obtained. APR(+) chronic chagasic had worse nutritional status than APR(-) ones: weight = 49.0 vs 54.5 kg; BMI = 17.5 vs 20.6 kg/m2 (median p < 0.05). CVAG T. cruzi nests frequency were similar (43.3% and 43.9%, respectively) between both Groups. We conclude that APR(+) chronic chagasic had worse nutritional status than APR(-) ones, and that APR development did not change the CVAG T. cruzi nests frequency.

[Trichobilharzia franki n. sp.--the cause of swimmer's dermatitis in southwest German dredged lakes]. / Trichobilharzia franki n. sp.--die Ursache für Badedermatitiden in südwestdeutschen Baggerseen.

Ocellate furcocercariae from the lymnaeid snail Radix auricularia have been identified as causative agents of swimmer's itch, which has become increasingly common in the 'Tunisee' near Freiburg. On an average 11.0%, maximally 25.0%, of the snails were parasitized with these trematode larvae. The Trichobilharzia parasitizing rate in the intermediate hosts found here was thus approximately 10-100 times higher than the Trichobilharzia prevalence described so far. Dwarf mallards (Anas platyrhynchos, blood red) were experimentally infected with Trichobilharzia cercariae from the 'Tunisee'. From the 13th day p.i. miracidia could be found in their faeces by means of the hatching method. The trematode eggs had the shape of an elongated spindle, with a pointed and a rounded end. The sexually differentiated adult worms were localized only in the hepatic and enteric veins. They had an average length of 4.0 mm (3.2-4.6 mm) and a width of 125 microns. Their tegument was strongly folded and had tegumental spines in the oral and ventral suckers, in males in addition along the canalis gynaecophorus. The most striking internal organ was the gut filled with hematin and separated in 2 caeca at its anterior end. Its form and localisation as well as those of the sexual organs were important criteria for the differentiation of the different Trichobilharzia species. The Trichobilharzia species found in the 'Tunisee' clearly differed from Trichobilharzia szidati both morphologically and physiologically. The latter has been considered, until now, to be the main causative agent of swimmer's itch in Germany. Moreover, the adult trematodes from the 'Tunisee' could not be associated with any other species of this genus. We propose therefore the name Trichobilharzia franki n. sp. for the species from the Tunisee.

Possible role of an adrenal parasite reservoir in the pathogenesis of chronic Trypanosoma cruzi myocarditis.

The possible contribution of parasitism of the central vein of the adrenal gland (CVAG) to chronic Trypanosoma cruzi myocarditis was assayed by comparing the occurrence of nests of amastigotes in the left ventricular myocardium (LVM) and determining the number and extent of areas of focal leucocyte exudate (FLE) in Chagas disease patients with and without CVAG parasitism. The frequency of occurrence of T. cruzi nests in the LVM, as well as the FLE number and area, were greater among patients with CVAG parasitism. We therefore suggest that CVAG parasitism plays a role in the onset and intensity of chronic T. cruzi myocarditis.