Direct Examination Of Blood Research Articles

Low diagnostic performance of thick blood smears of 50 µl in comparison with direct examination of 10 µl blood and the leukoconcentration technique of 5ml blood among loiasis-suspected patients with low microfilaremia in Gabon, Central Africa, using the STARD-BLCM guidelines

BackgroundThe aim of this study was to determine performance indicators of thick blood smears of 50 µl (TBS-50), following the Standards for the Reporting of Diagnostic Accuracy Studies–Bayesian Latent Class Model (STARD-BLCM) guidelines. TBS-50 was compared with two common parasitological techniques—direct examination of 10 µl blood and a leukoconcentration of 5 ml—for the diagnosis of microfilaremic loiasis.MethodsThe study population was recruited among patients of the Department of Parasitology-Mycology-Tropical Medicine over a period of 1 year. Age, sex, symptoms, and eosinophilia variables were recorded from laboratory registers and medical files. Direct examination of 10 µl of blood, TBS-50, and the leukoconcentration technique with 5 ml of blood were performed for each patient. The classical formula and BLCM were used to determine the diagnostic accuracy of the three techniques as well as the prevalence of microfilaremic loiasis. Three models were built within the framework of BLCM—the BLCM model I and alternative models II and III—for sensitivity analysis.ResultsIn total, 191 patients consented to be included. The direct blood examination and TBS-50 yielded comparable qualitative and quantitative results. Hence, they are reported together. The prevalence of Loa loa microfilaremia was 9.4% (95% CI 5.7–14.5; n = 18/191) with direct blood examination/TBS-50 and 12.6% [8.2–18.1] (n = 24/191) for leukoconcentration. Comparing TBS-50 with the leukoconcentration method using the classical formula, the sensitivity was 75.0% [53.3–90.2], specificity was 100.0% [97.8–100.0], the positive predictive value was 100.0% [81.5–100.0], and the negative predictive value was 96.5% [92.6–98.7]. The prevalence of microfilaremic loiasis was estimated at 9.7% [6.2–13.7] using BLCM model I. The outputs of BLCM model I showed sensitivity of 78.9% [65.3–90.3], specificity of 100.0% [99.3–100.0], a positive predictive value of 99.1% [87.2–100.0], and a negative predictive value of 93.0% [87.3–97.7] for direct blood examination/TBS-50.ConclusionsTBS-50 demonstrates low sensitivity relative to two other techniques. In one in five cases, the result will be falsely declared negative using these methods. However, this method can be deployed with limited funds.Graphical

Occurrence of Dirofilaria immitis in cats from the Aegean region in Turkey

Dirofilaria immitis (D. immitis) is a vector-mediated zoonotic parasite that can cause significant cardiopulmonary problems in humans and animals. Although dogs are the main hosts of the parasite, in recent years, its importance has been increasing in cats, especially in endemic areas. This study aims to determine the occurrence of D. immitis infection in cats in the Aegean region, Turkey. The animal material of the study consisted of 200 cats of different breeds and ages (at least 1 year old) and both sexes. The cats were tested for D. immitis and Feline Immunodeficiency Virus (FIV) antibodies and Feline Leukaemia Virus (FeLV) antigen with commercial immuno-chromatographic test kits. In addition, blood samples were examined for microfilariae using a direct blood smear technique and the modified Knott’s test. Out of 200 cats, one (0.5%) cat was seropositive for D. immitis, 15 (7.5%) cats were seropositive for FIV, and one (0.5%) cat was seropositive for FeLV. One cat seropositive for D. immitis was showing signs of active heartworm infection. All samples were found negative for microfilariae by direct blood examination and the modified Knott’s method. This study is the first report of the occurrence of D. immitis in the Aegean Region, with a seroprevalence of 0.5%. Also, it provides evidence that cats in the Aegean region are at risk of becoming infected with D. immitis.

Clinical profile of leptospirosis and role of various diagnostic methods, a hospital based prospective observational study

Leptospirosis is a potentially life-threatening zoonotic disease of worldwide distribution. Accurate diagnosis and prompt treatment are essential to minimize morbidity and mortality. The current study was conducted to analyse the clinical profile of leptospirosis and the diagnostic yield of various diagnostic methods. The present study was a cross-sectional study. A total of 60 patients who were suspected of leptospirosis were enrolled in the study. Direct examination of blood was done using dark-ground microscopy, the culture was done by inoculation of the blood sample into the EMJH medium, antibodies against Leptospira was demonstrated using Panbio IgM ELISA kit, and antigen products were demonstrated using polymerase reaction (PCR) with primers G1and G2.The study population included 63% of males and 37% females. A majority of 38% of the study subjects were farmers. Pallor and icterus are the predominant clinical signs found among 96% of the study population. IgM ELISA has labelled the highest number i.e. 55 (91.66%) of subjects as positive. The number of subjects diagnosed positive by PCR, culture and Dark ground microscopy (DGM) were 33 (55.00%), 22 (36.66%) and 12 (20%) subjects respectively.Leptospirosis proves to be an important health concern. Prominent clinical conditions were observed. IgM-ELISA proved superior to Dark ground microscopy (DGM), Culture and Polymerase chain reaction (PCR) and suitable for early diagnosis of leptospirosis.

Mastoïdite aiguë atypique révélant une leucémie de Burkitt chez une enfant de 7 mois

A 7-month-old girl presented with left acute mastoiditis and a white blood cell count of 79,000/mm(3). A surgically obtained bacteriological sample showed Streptococcus pneumoniae. Direct blood examination revealed leukemic blast cells. Histological samples showed leukemic infiltration of the left temporal bone. The final diagnosis was Burkitt's leukemia with left temporal bone leukemic infiltration. The patient received chemotherapy according to the LMB 2001 protocol from the Société française d'oncologie pédiatrique. Clinical, biological, and imaging follow-up 30 months after the end of treatment showed remission with complete recovery in the left temporal bone. Atypical presentation of acute mastoiditis (AM) should prompt investigation into whether there is a rare underlying pathology, such as a hemopathy, histiocytosis, or solid tumor. The first sign of leukemia may be acute middle ear disease. To our knowledge, no other cases of Burkitt's leukemia with temporal bone leukemic infiltration presenting as AM have been reported in a child under 1 year of age.

Morphometric Study of Microfilariae of Dirofilaria spp. on Dogs

The authors of this study tried to differentiate microfilariae of Dirofilaria spp. on dogs, using Knott's modified method based on morphological characters and dimensions obtained: length and width. 188 blood samples were collected for this study from dogs in Timis and Hunedoara counties. The presence of the microfilariae in blood was revealed by the direct examination of blood between blade and slide and through Knott's modified method. Of the samples examined, eight samples were positive for microfilariae. After observing the microfilariae, we began to identify the species according to the morphology of Dirofilaria la rvae. The microfilariae were measured using Olympus microscope with a cell analysis software. All eight samples were positive for infection with Dirofilaria repens. The positive samples were also tested with other methods: Diro test -Speed ® Diro / heartworm (Bio Veto Test, France), ELISA and molecular techniques. The results obtained from the eight positive samples were read in conjunction with existing data in the literature.

ISOLAMENTO DE TRYPANOSOMA EVANSI EM BOS TAURUS INDICUS NO PANTANAL NORTE, BRASIL

ISOLATION OF TRYPANOSOMA EVANSI IN BOS TAURUS INDICUS IN NORTHERN PANTANAL, BRAZIL A herd of 200 animals, originally raised in cerrado areas, were transferred to Mato Grosso's Pantanal, after which 5 cows died. Previous clinical analysis had shown progressive cachexy – though appetite was maintained, aggressiveness, submandibular edema, incoordination, frequent falls, and recumbency. Hematological results included anemia, leukocytosis, thrombocytosis, and increased platelet aggregation. Direct blood examination, such as thick drop smears and Woo tests, were negative for T. evansi, whereas IIF and PCR tests were positive. A severely affected cow was euthanized in extremis. It had signs of marked cachexy, submandibular edema, infarction of lymph nodes, sternal recumbency, and pleurothotonus. Histological and necropsy findings revealed lymphadenomegaly, splenic lymphoid hyperplasia, and lymph nodes showing immature cells or blasts. Wistar rats were inoculated by intraperitoneal blood injection at the moment of euthanasia and T. evansi strains were isolated. It was not possible to reproduce the clinical disease by inoculating cows with the same strain, although re-isolation of the agent from inoculated rats was achieved up to 30 days after inoculation in the cow. This study reports a case of trypanosomiasis by T. evansi in a symptomatic cow in Northern Pantanal.

Mother-child transmission of Chagas disease: could coinfection with human immunodeficiency virus increase the risk?

A study was conducted on all newborns from mothers with Chagas disease who were attended at Hospital Donación F. Santojanni between January 1, 2001, and August 31, 2007. Each child was investigated for the presence of Trypanosoma cruzi parasitemia through direct examination of blood under the microscope using the buffy coat method on three occasions during the first six months of life. Serological tests were then performed. Ninety-four children born to mothers infected with Trypanosoma cruzi were attended over the study period. Three of these children were born to mothers coinfected with the human immunodeficiency virus. Vertical transmission of Chagas disease was diagnosed in 13 children, in all cases by identifying parasitemia. The overall Chagas disease transmission rate was 13.8% (13/94). It was 100% (3/3) among the children born to mothers with HIV infection and 10.9% (10/91) among children born to mothers without HIV [Difference = 0.89; CI95 = 0.82-0.95; p = 0.0021]. We concluded that coinfection with HIV could increase the risk of vertical transmission of Chagas disease.

Seroprevalence of Trypanosoma cruzi in raccoons from South Carolina and Georgia.

Trypanosoma cruzi, the causative agent of American trypanosomiasis or Chagas' disease, is of both medical and veterinary importance as is evidenced by chronic phase myocarditis in humans and dogs. Further, T. cruzi has been reported from over 20 species of wildlife reservoir hosts in the USA, with raccoons (Procyon lotor) and opossums (Didelphis virginiana) being the most common. Whereas previous studies on T. cruzi in raccoons have included only culture and direct examination of blood, the indirect immunofluorescent antibody test (IFAT) was used in the current study to detect anti-T. cruzi antibodies in the serum of raccoons. Of 221 raccoons trapped at 13 sites representing the five physiographic regions of South Carolina plus five sites in the Piedmont region of Georgia (from April 1997 to February 2000), 104 (47%) were seropositive. A higher seroprevalence in raccoons was observed in the coastal regions, with seroprevalence in the Lower Coastal Plain South (61%) being significantly higher than that in the Foothills (37%), Piedmont (42%), and Upper Coastal Plain (40%) regions. However, at a seroprevalence of 52%, the Lower Coastal Plain North was not significantly different from any other region. Although more female raccoons were infected than males, no statistical difference in prevalence was observed between sexes. The high seroprevalence of T. cruzi in raccoons, together with a few reports of wildlife isolates being infective for other wildlife species and domestic/laboratory animals, suggests that risk of T. cruzi infection may be higher than previously suspected.

Synanthropic rodent reservoirs of Trypanosoma (Schizotrypanum) cruzi in the valley of Caracas, Venezuela.

Direct blood examination and xenodiagnosis of 47 synanthropic rodents (Rattus rattus, R. norvegicus, Mus musculus) captured in the valley of Caracas, Venezuela, revealed trypanosomal infections in 12 R. rattus, 10 with T. lewisi and 2 with T. cruzi. Of the latter the course of parasitemia, the pleomorphism of the bloodstream trypomastigotes, tissue in naturally and experimentally infected rats and mice, host mortality, morphology of fecal parasites in Rhodnius prolixus used for xenodiagnosis, and infectivity of the bug feces for NMRI mice, were all characteristic of Trypanosoma (Schizotrypanum) cruzi. One rat, with a patent parasitemia, had numerous nests of amastigotes in cardiac muscle and moderate parasitism of the smooth muscle of the duodenum and of skeletal muscle. Mice inoculated with fecal flagellates from the bugs had moderate tissue tropism in the same organs and also in the colon and pancreas. The possible role of R. rattus in the establishment of foci of Chagas' disease in Caracas is discussed.

Investigation on the possibility of spontaneous cure of mice infected with different strains of Trypanosoma cruzi.

Seventy Swiss mice chronically infected with different strains of Trypanosoma cruzi, with persistently negative parasitemia on routine blood examination were parasitologically investigated to find out whether spontaneous cure occurred. Duration of infection varied from 90 to 250 days in the initial phase of this investigation. Parasitological tests consisted of daily direct blood examination performed during at least 25 days, followed by xenodiagnosis and subinoculation of blood into newborn mice. Mice that persisted negative were treated with Cyclophosphamide with one dose of 250 mg/kg of body weight and then investigated by direct blood examination, xenodiagnosis and subinoculation. A second dose of 250 mg/kg b. w. was given to the persistently negative mice. With one single exception, all mice showed positive parasitological tests in the different stages of the present investigation and we conclude that spontaneous cure did not occur in this group, which is representative of the chronic infection with different strains of T. cruzi.

Didelphis marsupialis: a primary reservoir of Trypanosoma cruzi in urban areas of Caracas, Venezuela.

Direct blood examination and xenodiagnosis of 45 sylvatic, peridomestic or domestic mammals from the Caracas valley, Venezuela, revealed trypanosome infection in six of the 24 opossums, Didelphis marsupialis, collected in urban areas. Isolates were successfully made of trypanosomes from four of the opossums, using the parasites which developed in Rhodnius prolixus fed on the infected opossums to infect NMRI mice. The prepatent period, course of parasitaemia, morphology of bloodstream trypomastigotes, tissue tropism of parasites in the opossums and/or mice, host mortality, morphology of parasites in the bugs, and infectivity to mice of parasites in the faeces of infected bugs, were all characteristic of Trypanosoma (Schizotrypanum) cruzi. In mice, the parasites showed marked myotropism; the heart, skeletal muscle and the smooth muscle of the urinary bladder, penis, prostate, seminal vesicle, lung, stomach, jejunum and colon were frequently invaded, and pseudocyts were also occasionally found in the liver, brain and pancreas. The significance of the invasion of the genito-urinary structures as a possible alternative parasite transmission route is discussed. The possible role of D. marsupialis, as a primary reservoir of T. cruzi, in the establishment of foci of Chagas' disease in Caracas and other Latin American cities, is emphasized.

The prevalence of Trypanosoma cruzi infection in armadillos collected at a site near New Orleans, Louisiana.

A study was made of the prevalence of Trypanosoma cruzi infection in armadillos at a site near New Orleans, Louisiana, where the flagellate was known to occur. Blood cultures, microscopic examination of blood, and direct agglutination tests on sera were employed in 80 armadillos. T. cruzi was isolated in culture from 23 of 80 animals; identity of the parasite was confirmed in mice inoculated with each of the isolates. Only 2 animals were positive by direct examination of blood. Serologic evidence of infection was obtained for the 23 animals that were positive by culture, and for at least 7 of those animals with negative or contaminated cultures. These results suggest that the armadillo is a reservoir of this zoonosis.

Trypanosoma cruzi-like bloodstream trypomastigotes in bats from the State of Piauí, Northeastern Brazil.

One-hundred and thirty-five bats from 12 species were examined for thepresence of trypomastigotes by means of direct blood examination, xenodiagnosis, and hemoculture. Of those, 44 specimens (32.6%) from 8 species were infected with trypanosomes. Phyllostomus discolor discolor presented the highest rate of infection, being captured only in one locality, while Phyllostomus hastatus hastatus captured in four localities showed high rates. Two species, Anoura geoffroyii and Pteronotus (Phillodia) pamelli rubiginosa, were found infected by T. cruzi-like trypanosomes, apparently described for thefirst time. Flagellates from Artibeus jamaisensis jamaisensisa and A. geoffroyii were able toproduce detectable parasitaemia in young mice. One triatomine bug was found infected in natural conditions, Triatoma brasiliensis was associated with a P.h. hastatus colony, in which six captured bats were also found infected.

Trypanosome infections in the marmoset (Saguinus geoffroyi) from the Panama Canal Zone.

From August 1973 through May 1974 a total of 148 marmosets (Saguinus geoffroyi) were examined for blood parasites. Parasites were detected in 93.2% of the monkeys. Direct examination of blood revealed 82.4% infected with trypanosomes; Trypanosoma cruzi was seen in 1.3% of the animals examined T. minasense in 52.7% and T. rangeli in 25%. However, the use of several diagnostic tests (direct microscopic examination, hemoculture, xenodiagnosis, and animal inoculation) in 15 marmosets revealed T. cruzi in 40%, T. rangeli in 93% and T. minasense in 87%. The high rate of infection among marmosets suggests that they are important natural hosts of T. cruzi and T. rangeli in the Panama Canal Zone.

Frequency and distribution of Trypanosoma cruzi and Trypanosoma rangeli in the Republic of Panamá.

To provide information on the frequency and distribution of human trypanosomiasis in the Republic of Panamá, we carried out a survey of the rural population in the nine provinces and the San Blas Territory. After direct examination of blood and hemoculture procedures, we examined 12,975 blood samples, corresponding to 10,570 persons, for trypanosomes from January 1965 through December 1969. Trypanosoma cruzi and Trypanosoma rangeli were more prevalent in the rural areas of Central Panamá, including the provinces of Panamá, Colón, and Coclé. Infections with T. rangeli were also recorded in Darién and Bocas del Toro Provinces. Parasitemia was not detected in blood samples examined from Herrera, Los Santos, Veraguas, and Chiriquí Provinces. The samples from the San Blas Territory were also negative. In Central Panamá, both T. cruzi and T. rangeli occur in the same localities. In 16 communities studied in Panamá Province, the infection rate varied from 0.5% to 8.8%. T. rangeli was six times more prevalent than T. cruzi. The annual variation in the prevalence of infections during the 5 years of this study was determined for the villages of Mendoza. Altos del Jobo, and Cerro Cama. Of 160 persons found positive for trypanosomes, 75% were less than 16 years old. Trypanosomes were more frequently detected in children 6 to 10 years old.

Antigens Common to Plasmodium and Haemoproteus

Summary 1. Complement fixation tests were carried out in a group of 146 pigeons. 2. Positive reactions were obtained in all pigeons with a microscopically diagnosed H. columbae infection and in the majority of latent chronic infections. The complement fixation tests particularly with P. gallinaceum antigen was found to be more reliable than direct blood examination for the diagnosis of H. columbae. 3. Antigens prepared from P. gallinaceum and H. columbae gave specific and group reactions. 4. The existence of serological cross reactions between the genus Plasmodium and the genus Haemoproteus was demonstrated. 5. These results are significant in the light of recent findings of primary tissue forms in Plasmodium.

CHAPTER 4.: Observations Made on the Direct Examination of Blood from Patients Treated with Sulfanilamide Preparations.1

Acta Medica ScandinavicaVolume 110, Issue S130 p. 49-55 CHAPTER 4.: Observations Made on the Direct Examination of Blood from Patients Treated with Sulfanilamide Preparations.1 First published: January/December 1942 https://doi.org/10.1111/j.0954-6820.1942.tb11919.x 1 Some of the investigations published in this chapter have been reported previously by Svabtz and Kallner. 4-421267 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume110, IssueS130January/December 1942Pages 49-55 RelatedInformation

WEIL'S DISEASE

<h3>To the Editor:—</h3> In referring to your editorial on Weil's disease (The Journal, Oct. 11, 1941, p. 1266), permit me to make one suggestion. In speaking of the laboratory tests in the diagnosis, the editorial states that "... dark field examination of centrifuged blood during the first stage and of the urine after the tenth day are the most important." Unfortunately, in practice the pitfalls involved in the direct examination of blood by dark field illumination are such that little reliance can be placed on this method alone, even by experienced laboratory workers. Recently I had occasion to speak with Dr. E. A. Fennel of Honolulu on this very subject. I had just completed a study on canine leptospirosis (Canine Leptospirosis in Pennsylvania,<i>J. Infect. Dis.</i><b>69</b>:131-137 [Sept.-Oct.] 1941). In this study numerous blood specimens were examined serologically (agglutination-lysis test) and also by direct dark field illumination of centrifuged blood