Case Of Human Babesiosis Research Articles

Experimental in vitro transmission ofBabesiasp. (EU1) byIxodes ricinus

Babesia sp. (EU1), first characterized in 2003, has been implicated in human cases of babesiosis in Italy, Austria and Germany. It has been identified in roe deer and in its suspected tick vector, Ixodes ricinus, in several European countries. The aim of the present study was to validate the competence of I. ricinus as a vector of Babesia sp. (EU1) via experimental infections. For this purpose, a parasite strain isolated from roe deer was cloned in sheep erythrocytes. After experimental infections, parasite DNA was successfully amplified by PCR in both eggs and larvae originating from infected I. ricinus females and in the salivary glands of females exposed to Babesia sp. (EU1) as nymphs. We also demonstrate that infected females were able to transmit parasite DNA during a new blood meal. Together with previous epidemiological studies, these results validate I. ricinus as a competent vector for Babesia sp. (EU1).

Babesia Species Occurring in Austrian Ixodes ricinus Ticks

Babesiosis is a tick-transmitted disease of veterinary and medical importance. The first Austrian case of human babesiosis was recently recorded. In the current study, ticks at all life cycle stages (instars), including 853 Ixodes ricinus and 11 Haemaphysalis concinna ticks, from sampling sites throughout Austria were examined for the presence of Babesia spp. by using 18S rRNA gene PCR and sequencing, and the overall mean infection rate was 51.04%. The infection rates for sampling sites were highly variable, ranging from 0% to almost 100%. Different instars and different sexes were infected almost equally. Babesia isolates occurring in Austrian ticks were identified as Babesia divergens, Babesia divergens-like, and Babesia sp. strain DD by sequencing a fragment of the heat shock protein 70 gene and internal transcribed spacer regions 1 and 2. To our knowledge, this is the first investigation of Babesia spp. in Austrian ticks.

Human babesiosis in Germany: Just overlooked or truly new?

Tick-borne infections are among the more important vector-borne infections in the northern hemisphere. However, many facts pertaining to the epidemiology and pathogenesis of such diseases in Europe remain unclear. Human babesiosis in particular may have previously been overlooked in many parts of the world due to a lack of medical awareness and microbiological detection methods. Recently, the first two cases of human babesiosis were reported in Germany, occurring in vicinities where the presence of Babesia spp. in enzootic cycles was obvious for decades but where the risk of acquiring Babesia spp. either from ticks or from human blood products was not known before. It is important to note, though, that as with other tick-borne diseases, Babesia infections may arise in geographic areas where they have not been recorded in the past. Better molecular detection methods and strain typing of parasites are necessary to investigate the epidemiological distribution of zoonotic Babesia spp. in Europe and to clarify whether their virulence or transmissibility is strain-dependent. Therefore, further seroepidemiological and molecular epidemiological studies are urgently needed to learn more about the distribution and medical relevance of these pathogens in various parts of Europe in general and in Germany in particular.

First Case of Human Babesiosis in Korea: Detection and Characterization of a Novel Type of Babesia sp. (KO1) Similar to Ovine Babesia

We report on the first case of human babesiosis in Korea. The intraerythrocytic parasite (KO1) in the patient's blood mainly appeared as paired pyriforms and ring forms; but Maltese cross forms were not seen, and the parasite showed morphological features consistent with those of the genus Babesia sensu stricto. The sequence of the 18S rRNA gene of KO1 was closely related to that of Babesia spp. isolated from sheep in China (similarity, 98%). The present study provides the first evidence of the presence of a hitherto unidentified, new type of Babesia parasite capable of infecting humans.

First case of human babesiosis in Germany – Clinical presentation and molecular characterisation of the pathogen

Babesiosis is a common infection of animals and is gaining increasing attention as an emerging tick-borne zoonosis of humans in Europe. Here we report on the first case of human babesiosis in Germany in a 63-year-old splenectomised German patient with a relapse of nodular lymphocyte-predominant Hodgkin's lymphoma. After treatment with a chimeric anti-CD20 antibody preparation (Rituximab), the patient was hospitalised because of anaemia and dark urine from haemoglobinuria. Presumptive diagnosis of babesiosis was made based on piriform parasitic erythrocytic inclusions in peripheral blood smears and confirmed by Babesia-specific 18S rDNA PCR. Sequence analysis revealed a >99% homology of the amplicon with the recently described EU1 organism clustering within the Babesia divergens/Babesia odocoilei complex. Despite treatment with quinine and clindamycin the patient relapsed and developed chronic parasitaemia requiring re-treatment and long-term maintenance therapy with atovaquone before he eventually seroconverted and the parasite was cleared. Our findings suggest that human babesiosis occurs in Germany and can take a chronic course in immunocompromised individuals.

Erythema figuratum in septic babesiosis

Babesiosis is a rare worldwide-distributed protozoal zoonosis caused by a haemoprotozoan of the genus Babesia, transmitted through bites of tick of the genus Ixodes. The first demonstrated case of human babesiosis in the world was discovered in Europe, in 1957. However, most of the cases were reported later in the north-east of the United States where Babesia microti has been the cause of over 300 cases of human babesiosis since 1969. In Europe, the most severe cases are observed in asplenic patients infected by a parasite of cattle, the Babesia divergens. Only two cases of babesiosis have been reported in Spain. We present a case of erythema figuratum associated to septic babesiosis in a non-splenectomized man, which is currently the third case of babesiosis in Spain.

Identity of the causal agents of human babesiosis in Europe

Most cases of human babesiosis are caused either by Babesia divergens in Europe or Babesia microti in America. B. microti, once regarded as a single species, occurs as a world-wide species complex and although both phenotypic and genotypic features lend support to suggestions that zoonotic B. microti may occur in Europe, convincing medical evidence is lacking. Several B. divergens-like parasites have emerged in the last few years, but 18S rRNA gene analysis suggests that B. divergens ‘sensu stricto’ is restricted to European (and North African) cattle. Some of the B. divergens-like parasites only differ from the bovine type by a few bases, and it remains to be determined whether this is sufficient to accord them separate species status. Comparative biology should support genetic data in taxonomic studies of both B. divergens and B. microti.

COMPARATIVE INFECTIVITY OF BABESIA DIVERGENS AND A ZOONOTIC BABESIA DIVERGENS–LIKE PARASITE IN CATTLE

Babesia divergens-like parasites identified in human babesiosis cases in Missouri and Kentucky and in eastern cottontail rabbits (Sylvilagus floridanus) on Nantucket Island, Massachusetts, share identical small subunit ribosomal RNA gene sequences. This sequence is 99.8% identical to that of Babesia divergens, suggesting that the U.S. parasite may be B. divergens, a causative agent of human and bovine babesiosis in Europe. Holstein-Friesian calves were inoculated with cultured Nantucket Island Babesia sp. (NR831) and B. divergens parasites and monitored by clinical signs, Giemsa-stained blood films, PCR, and culture. The NR831 recipients did not exhibit clinical signs of infection and remained negative for all assays. The B. divergens recipients developed clinical infections and became positive by all assays. NR831 recipients were fully susceptible upon challenge inoculation with B. divergens. This study confirms that the Nantucket Island Babesia sp. is not conspecific with B. divergens based on host specificity for cattle.

Demonstrable parasitemia among Connecticut blood donors with antibodies to Babesia microti

Reports of transfusion-transmitted Babesia microti have risen steadily during the past several years, reflecting a concurrent increase in US cases of human babesiosis. Although several studies have measured B. microti antibodies in blood donors, little is known about associated parasitemia and the inherent risk of transmitting the parasite by transfusion. Donations from blood donors located in Babesia-endemic and nonendemic areas of Connecticut were tested for B. microti antibodies from July through September. Subsequently, an additional blood sample was collected from selected seropositive donors and tested by nested polymerase chain reaction (PCR) for B. microti nucleic acids. A total of 3490 donations, 1745 each from endemic and nonendemic areas, were tested for B. microti antibodies; 30 (0.9%) were confirmed as positive and seroprevalence rates peaked in July. Significantly more seropositive donations were from endemic areas (24, 1.4%) than nonendemic areas (6, 0.3%). Ten (53%) of 19 seropositive donors subsequently tested by PCR were positive. B. microti seroprevalence was highest in those areas of Connecticut where the parasite is endemic. More than half of seropositive donors tested had demonstrable parasitemia, indicating that many are at risk for transmitting B. microti by blood transfusion. Three donors were identified as parasitemic in October, suggesting that donors may be at risk for transmitting the parasite outside of the peak period of community-acquired infection.

Molecular Characterization of Human Pathogen Babesia EU1 in Ixodes ricinus Ticks From Slovenia

New cases of human babesiosis were recently reported in Europe. The etiological agent was identified as Babesia EU1, a zoonotic pathogen with previously unreported molecular characteristics. On the basis of a comparison of the complete babesial 18S rRNA gene, we have generated strong molecular evidence that Ixodes ricinus ticks from Slovenia are infected with EU1.

Babesia microti, Upstate New York

Five cases of human babesiosis were reported in the Lower Hudson Valley Region of New York State in 2001. An investigation to determine if Babesia microti was present in local Ixodes scapularis ticks yielded 5 positive pools in 123 pools tested, the first detection of B. microti from field-collected I. scapularis in upstate New York.

Detection of Babesia microti-like parasite in filter paper-absorbed blood of wild rodents.

The first case of human babesiosis was reported in Japan. The epidemiology of this disease in Japanese nature remains unclear. In this study, 97 common field mice captured in Hokkaido, Japan, were examined. Blood specimens absorbed onto filter papers were eluted and tested by nested PCR using specific primers for the B. microti nuclear small subunit rRNA genome. Twenty-three percent (11/47) of Apodemus speciosus and four percent (2/50) of Clethrionomys rufocanus were positive. The 159-bp primary sequences of PCR products tested exhibited 97.5% and 96.8% homology with those of the human isolate in Japan and of U.S. strains of B. microti, respectively.

Human babesiosis in Japan: isolation of Babesia microti-like parasites from an asymptomatic transfusion donor and from a rodent from an area where babesiosis is endemic.

To determine the source of infection for the Japanese index case of human babesiosis, we analyzed blood samples from an asymptomatic individual whose blood had been transfused into the patient. In addition, we surveyed rodents collected from near the donor's residence. Examination by microscopy and PCR failed to detect the parasite in the donor's blood obtained 8 months after the donation of the blood that was transfused. However, we were able to isolate Babesia parasites by inoculating the blood sample into SCID mice whose circulating red blood cells (RBCs) had been replaced with human RBCs. A Babesia parasite capable of propagating in human RBCs was also isolated from a field mouse (Apodemus speciosus) captured near the donor's residential area. Follow-up surveys over a 1-year period revealed that the donor continued to be asymptomatic but had consistently high immunoglobulin G (IgG) titers in serum and low levels of parasitemia which were microscopically undetectable yet which were repeatedly demonstrable by inoculation into animals. The index case patient's sera contained high titers of IgM and, subsequently, rising titers of IgG antibodies, both of which gradually diminished with the disappearance of the parasitemia. Analysis of the parasite's rRNA gene (rDNA) sequence and immunodominant antigens revealed the similarity between donor and patient isolates. The rodent isolate also had an rDNA sequence that was identical to that of the human isolates but that differed slightly from that of the human isolates by Western blot analysis. We conclude that the index case patient acquired infection by transfusion from a donor who became infected in Japan, that parasitemia in an asymptomatic carrier can persist for more than a year, and that A. speciosus serves as a reservoir of an agent of human babesiosis in Japan.

Babesiosis

A case of human babesiosis is presented. This case emphasizes the need to consider tick-borne disease in anyone who presents with prolonged and undulating fevers, chills, headache, myalgias, and arthralgias. This holds true particularly in areas endemic for tick-borne diseases, even in the absence of a history of tick bite. These symptoms, associated with signs of intravascular hemolysis, thrombocytopenia, and renal insufficiency in a patient who resides in, or with recent travel to, the Northeastern United States, strongly suggest a diagnosis of babesiosis.

Transfusion-acquired, autochthonous human babesiosis in Japan: isolation of Babesia microti-like parasites with hu-RBC-SCID mice.

We have isolated piroplasms from a patient who developed the first case of human babesiosis in Japan by using NOD/shi-scid mice whose circulating erythrocytes (RBCs) had been replaced with human RBCs (hu-RBC-SCID mice). Following inoculation of the patient's blood specimen into hu-RBC-SCID mice, parasites proliferated within the human RBCs in the mice, resulting in a high level of parasitemia. Parasite DNA was prepared from blood samples of the patient and the mice, and the nuclear small-subunit rRNA gene (rDNA) was amplified and sequenced. Both DNA samples gave rise to identical sequences which showed the highest degree of homology (99.2%) with the Babesia microti rDNA. Because the patient had received a blood transfusion before the onset of babesiosis, we investigated the eight donors who were involved. Their archived blood samples were analyzed for specific antibody and parasite DNA; only a single donor was found to be positive by both tests, and the parasite rDNA sequence from the donor coincided with that derived from the patient. The donor's serum exhibited a high antibody titer against the isolate from the patient, whereas it exhibited only a weak cross-reaction against B. microti strains isolated in the United States. We conclude that the first Japanese babesiosis case occurred due to a blood transfusion and that the etiological agent is an indigenous Japanese parasite which may be a geographical variant of B. microti. Our results also demonstrated the usefulness of hu-RBC-SCID mice for isolation of parasites from humans and for maintenance of the parasite infectivity for human RBCs.

Human babesiosis: an emerging tick-borne disease

Human babesiosis is an important emerging tick-borne disease. Babesia divergens, a parasite of cattle, has been implicated as the most common agent of human babesiosis in Europe, causing severe disease in splenectomized individuals. In the US, Babesia microti, a babesial parasite of small mammals, has been the cause of over 300 cases of human babesiosis since 1969, resulting in mild to severe disease, even in non-splenectomised patients. Changing ecology has contributed greatly to the increase and expansion of human babesiosis in the US. A relatively recently described babesial parasite, the WA1-type, has been shown to be the causative agent in seven human cases in the western US. This parasite is closely related to babesial parasites isolated from large wild ungulates in California. Like B. microti, WA1-type parasites cause mild to severe disease and the immunopathogenesis of these parasites is distinctly different from each other in experimental infections of hamsters and mice. A B. divergens-like parasite was also identified as the cause of a fatal human babesiosis case in Missouri. Isolated cases of human babesisosis have been described in Africa and Mexico, but the causative parasites were not well characterized. Standard diagnostic techniques for human infection, such as examination of Giemsa-stained thin blood smears and serology, have been complemented with molecular techniques, such as PCR. Current treatment for babesiosis is focused on a regimen of clindamycin and quinine, although new drugs have shown promise. Prevention of infection relies on self-monitoring for the presence of ticks and, in some locations, targeted application of pesticides to decrease tick abundance. Identification of human infection with Babesia spp. will probably increase as physicians and the public become more aware of the disease, as people live and recreate in rural tick-infested areas, and as the numbers of immunocompromised individuals increase.

Babesiosis--a dangerous infection for splenectomized children and adults

Babesiosis is a world-wide distributed protozoal zoonosis, and Babesia spp. are the most ubiquitous of the blood parasites of mammals, except the trypanosomes. The tick-transmitted protozoa infect various vertebrate reservoir hosts, like rodents, cattle and horses. Approximately 100 million cattle is exposed to the disease. In tropical and subtropical regions the infection causes considerable losses in livestock industry, but clinical cases of human babesiosis in these areas have not certainly been identified. In 1957, the first case of human babesiosis in an asplenic Yugoslav farmer was reported (35). Hitherto, hundreds of cases of human babesiosis in adults and children from Europe and the U.S., with a broad range of clinical presentations, have been published (3, 4, 38). Most of the patients suffer from mild to moderate symptoms, whereas in asplenic individuals a fatal course of the infection prevails. Tick-bites in areas where human babesiosis occurs--mainly parts of Europe and the USA--can result in a deadly illness for persons without a spleen. The effect of treatment in splenectomized patients and when treatment is delayed, still is poor.

Human babesiosis in New York State: Review of 139 hospitalized cases and analysis of prognostic factors.

Babesiosis infections are infrequent, occur in limited geographic locations, and range from asymptomatic infection to severe illness and death. Descriptive clinical and epidemiological information on human babesiosis cases was collated from state communicable disease reports and medical records of patients hospitalized from 1982 to 1993. Univariate and multivariate analyses were performed to determine prognostic factors associated with severe disease outcome (hospitalization ending in death, duration of hospitalization > 14 days, or intensive care unit stay > 2 days). Between 1982 and 1993, 139 patients were hospitalized with babesiosis in New York State. Nine patients (6.5%) died, 35 (25.2%) were admitted to the intensive care unit, and 35 (25.2%) required hospitalization for more than 14 days. Mean age at first hospitalization was 62.5 years. Sixty-two percent were male, and 91% resided in Suffolk County, Long Island. The most common symptoms were fatigue/malaise/weakness (91%), fever (91%), shaking chills (77%), and diaphoresis (69%). Past medical records showed that 52% of patients had a history of chronic disease; 12% had a history of Lyme disease; 12% had undergone a splenectomy; and 2% had undergone a blood transfusion. There was a 12- to 14-day delay between onset of symptoms and initiation of appropriate antibiotic treatment. Univariate analyses showed alkaline phosphatase levels greater than 125 U/L, white blood cell counts greater than 5 x 10(9)/L, history of cardiac abnormality, history of splenectomy, presence of heart murmur, and parasitemia values of 0.04 or higher to be significantly associated with disease severity. Multiple logistic regression analyses indicated that male sex, alkaline phosphatase values greater than 125 U/L, and white blood cell counts greater than 5 x 10(9)/L remained strong predictors of severe outcome. Human babesiosis is a rare but debilitating and potentially fatal illness, especially in the elderly. Prompt disease diagnosis and treatment are essential but are often delayed, as seen in our series. This delay reinforces the need for enhanced public and physician education targeted toward residents and visitors to the few high-risk geographic areas where disease and Ixodes scapularis ticks are endemic. Patients presenting with certain prognostic indicators (male sex, alkaline phosphatase values > 125 U/L, and white blood cell counts >5 x 10(9)/L) require comprehensive and aggressive medical care to prevent further deterioration. Since babesiosis is only 1 of 3 currently recognized diseases transmitted by I scapularis ticks, primary prevention recommendations will also reduce human exposure to Lyme disease and human granulocytic ehrlichiosis.

Human babesiosis.

The first demonstrated case of human babesiosis in the world was reported in Europe, in 1957. Since then, a further 28 babesial infections in man have been reported in Europe. Most (83%) of the infections were in asplenic individuals and most (76%) were with Babesia divergens, a cattle parasite. Parasitaemias varied from 1%-80% of red blood cells. The usual clinical manifestations of severe B. divergens infection were severe intravascular haemolysis with haemoglobinuria. The most efficient treatment consisted of a massive blood-exchange transfusion, followed immediately by chemotherapy with clindamycin. Hundreds of cases of human infection with Babesia spp. have been reported in the U.S.A. Most cases were infected by ticks carrying the rodent parasite B. microti, but other emerging. Babesia spp. (currently known as WA1, CA1, and MO1) are increasingly involved. Several cases were the result of blood transfusion. In terms of clinical manifestations, human infections with B. microti varied widely, from asymptomatic infection to a severe, rapidly fatal disease. Parasitaemia ranged between <1% and 85%. The splenectomized, the elderly, the immunocompromised and HIV-infected patients were predisposed to severe infection. Infection with B. microti often remained subclinical or asymptomatic and were only detected through serological surveys. The currently recommended treatment of symptomatic cases is quinine plus clindamycin. A few other cases of human babesial infection have been described in China, Egypt, Mexico, South Africa and Taiwan.

Human Babesiosis

Objective To describe a case of human babesiosis and review the literature on the disease. Material and Methods We describe a 62-year-old man with babesiosis, outline his clinical course and response to therapy, and discuss the use of the polymerase chain reaction for the diagnosis and monitoring of the infection. Results The onset of the disease was insidious, with fatigue, fever, weight loss, intermittently discolored urine, and anemia. Computed tomography of the abdomen revealed a small, shrunken spleen with an irregular border. With treatment, the symptoms gradually resolved. Although peripheral blood smears were negative soon after therapy, Babesia microti DNA was detected by polymerase chain reaction 53 days after initial examination. Conclusion The development of improved methods for diagnosis, including indirect immunofluorescent antibody assays and the polymerase chain reaction, provides more sensitive detection of the parasitemia associated with babesiosis. Use of these methods may help to delineate the complete clinical spectrum of this infection and its geographic distribution in the United States. To describe a case of human babesiosis and review the literature on the disease. We describe a 62-year-old man with babesiosis, outline his clinical course and response to therapy, and discuss the use of the polymerase chain reaction for the diagnosis and monitoring of the infection. The onset of the disease was insidious, with fatigue, fever, weight loss, intermittently discolored urine, and anemia. Computed tomography of the abdomen revealed a small, shrunken spleen with an irregular border. With treatment, the symptoms gradually resolved. Although peripheral blood smears were negative soon after therapy, Babesia microti DNA was detected by polymerase chain reaction 53 days after initial examination. The development of improved methods for diagnosis, including indirect immunofluorescent antibody assays and the polymerase chain reaction, provides more sensitive detection of the parasitemia associated with babesiosis. Use of these methods may help to delineate the complete clinical spectrum of this infection and its geographic distribution in the United States.