Babesiosis in Southeastern, Central and Northeastern Europe: An Emerging and Re-Emerging Tick-Borne Disease of Humans and Animals

There is now considerable evidence that in Europe, babesiosis is an emerging infectious disease, with some of the causative species spreading as a consequence of the increasing range of their tick vector hosts. In this review, we summarize both the historic records and recent findings on the occurrence and incidence of babesiosis in 20 European countries located in southeastern Europe (Bosnia and Herzegovina, Croatia, and Serbia), central Europe (Austria, the Czech Republic, Germany, Hungary, Luxembourg, Poland, Slovakia, Slovenia, and Switzerland), and northern and northeastern Europe (Lithuania, Latvia, Estonia, Iceland, Denmark, Finland, Sweden, and Norway), identified in humans and selected species of domesticated animals (cats, dogs, horses, and cattle). Recorded cases of human babesiosis are still rare, but their number is expected to rise in the coming years. This is because of the widespread and longer seasonal activity of Ixodes ricinus as a result of climate change and because of the more extensive use of better molecular diagnostic methods. Bovine babesiosis has a re-emerging potential because of the likely loss of herd immunity, while canine babesiosis is rapidly expanding in central and northeastern Europe, its occurrence correlating with the rapid, successful expansion of the ornate dog tick (Dermacentor reticulatus) populations in Europe. Taken together, our analysis of the available reports shows clear evidence of an increasing annual incidence of babesiosis across Europe in both humans and animals that is changing in line with similar increases in the incidence of other tick-borne diseases. This situation is of major concern, and we recommend more extensive and frequent, standardized monitoring using a “One Health” approach

Zoonotic Virus Seroprevalence among Bank Voles, Poland, 2002-2010

Bank voles in Poland are reservoirs of zoonotic viruses. To determine seroprevalence of hantavirus, arenavirus, and cowpox virus and factors affecting seroprevalence, we screened for antibodies against these viruses over 9 years. Cowpox virus was most prevalent and affected by extrinsic and intrinsic factors. Long-term and multisite surveillance is crucial.Non peer reviewe

Vertical Transmission of Babesia microti in BALB/c Mice: Preliminary Report.

Babesia spp. (Apicomplexa, Piroplasmida) are obligate parasites of many species of mammals, causing a malaria-like infection- babesiosis. Three routes of Babesia infection have been recognized to date. The main route is by a tick bite, the second is via blood transfusion. The third, vertical route of infection is poorly recognized and understood. Our study focused on vertical transmission of B. microti in a well-established mouse model. We assessed the success of this route of infection in BALB/c mice with acute and chronic infections of B. microti. In experimental groups, females were mated on the 1st day of Babesia infection (Group G0); on the 28th day post infection (dpi) in the post- acute phase of the parasite infection (G28); and on the 90th and 150th dpi (G90 and G150 group, respectively), in the chronic phase of the parasite infection. Pups were obtained from 58% of females mated in the post-acute phase (G28) and from 33% of females in groups G90 and G150. Mice mated in the pre-acute phase of infection (G0) did not deliver pups. Congenital B. microti infections were detected by PCR amplification of Babesia 18S rDNA in almost all pups (96%) from the experimental groups G28, G90 and G150. Parasitaemia in the F1 generation was low and varied between 0.01-0.001%. Vertical transmission of B. microti was demonstrated for the first time in BALB/c mice

Comparison of the overall parasitaemia during pregnancy and lactation, in females mated on post–acute phase on the 28^th and on chronic phase on the 90^th and 150^th day post infection with <i>B</i>. <i>microti</i>.

<p>Experimental groups are marked: Green bars- females paired with males on the 28^th day of infection (G28); Red bars- females paired with males on the 90^th and 150^th day of infection (G90 and 150).</p

Comparison of the course of <i>B</i>. <i>microti</i> infection in mice pregnant in different phases of the parasite infection.

<p>Level of <i>B</i>. <i>microti</i> parasitemia on the selected day post infection. Parasitemia is shown as a percentage of infected erythrocytes found in mouse peripheral blood, measured on the Giemsa-stained thin smears. Mice from the experimental groups were infected intraperitoneally with 5 x 10⁶<i>B</i>. <i>microti</i> iRBCs. Datum points are the mean for six animals. The experimental groups are marked: Blue line- females paired with males on the day of infection (G0); Green line- females paired with males on the 28^th day of infection (G28); Red line- females paired with males on the 90^th day of infection (G90); Violet line- females paired with males on the 150^th day of infection (G150). Black line- control female infected with <i>B</i>. <i>microti</i>, not mated. Each time point represents the mean value ± one SD. on the graphs.</p

PCR products from <i>B</i>. <i>microti</i> infected BALB/c mice on Midori Green stained gel.

<p><b>(A)</b> PCR products from experimental infected BALB/c mice on a different day post infection with <i>B</i>. <i>microti</i>. Lane 1–6 mice chronically infected with G90, G150, and G28 group, respectively; Lane 7–16 mice with acute and post-acute infection with G0, G28, G90, G150, and Gcontrol, respectively; Lane 19 –positive control, Line 20 –negative control; dpi- day post infection with <i>B</i>. <i>microti</i>; (B) PCR products from vertically infected BALB/c mice of the F1 generation. Lane 1 –positive control, Line 18 –negative control; Lane 2–4 mice on 60 dpb born from a mother within the G28, G90, G150 group, respectively. Lane 5–7 mice on 80 dpb born from a mother within the G28, G90, G150 group, respectively. Lane 8–10 mice on 100 dpb born from a mother within the G28, G90, G150 group, respectively. Lane 11–13 mice on 140 dpb born from a mother within the G28, G90, G150 group, respectively. Lane 14–15 mice on 190 dpb born from a mother within the G28 and G90 group respectively; M-marker site, 100bp DNA ladder; dpb- day post born; Gc- Gcontrol.</p

Peripheral blood smears from experimental BALB/c mice and their offspring demonstrating parasitised erythrocytes in different days post infections with <i>B</i>. <i>microti</i>.

<p>Microscopic images of infected erythrocytes under light microscopy of blood smears stained with Giemsa stain. <b>(A-F)</b> blood smears from mice with control and experimental G0, G28, G90, G150 groups. Pictures A and B showing pleomorphic rings and multiply-infected rbcs in the acute phase of the infection in: (A) a mouse (no 282) from group G28 on 5 dpi and (B) a mouse (no 1) from group Gcontrol on 7 dpi. Pictures C-D showing infected erythrocytes with single rings of <i>B</i>. <i>microti</i> in post-acute and chronic phase of infection in: (C) a mouse (no 285) from group G28 on 18 dpi, (D) a mouse (no 906) from group G90 on 28 dpi. Picture E demonstrates the divided form in the chronic phase of the infection in a mouse (no 1504) from group G150 on 97 dpi. Picture F demonstrates the ‘Maltese cross form’ in a mouse (no 904) with post-acute infection from group G90 on 28 dpi. <b>(G-I)</b> blood smears from mice in the suckling period. Pictures G-I showing infected erythrocytes (in the suckling period) of mice pregnant in the post-acute phase of the parasite infection in: (G) mouse no 281 from group G28 on the first day post weaned (49dpi), (H) mouse no 284 from group G28 on the 3rd day post weaned (51dpi), (I) mouse no 286 from group G28 on the 6th day post weaned (56 dpi). The course of infection with <i>B</i>. <i>microti</i> in these three mice is presented on <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137731#pone.0137731.g004" target="_blank">Fig 4</a>. <b>(J-L)</b> blood smears from mice of F1 generations. Pictures J-L showing infected erythrocytes in BALB/c pups vertically infected with <i>B</i>. <i>microti</i> in (J) mouse no 15012 on 50 dpb born from mother from the G150 group, (K-L) mouse no 1504 on 97 dpb born from mother from the G150 group, (L) the enlarged fragment of the image K. Scale bar represents 10 μm. Magnification x 1000 for A, C-J pictures and x600 for B, J-K pictures. Black arrows show infected erythrocytes.</p

Comparison of the reproductive success and features of congenital <i>B</i>. <i>microti</i> infection in pups of females from experimental groups.

<p>* Due to the lack of significant differences between females infected in the chronic phase of infection (G90 and G150) results are presented together.</p><p>**Births were reported in 8 dams but litters were obtained only from 7 females. One of the dams had eaten pups immediately after birth. Four scars were observed on the uterus but this data was not incorporated into the analysis.</p><p>Comparison of the reproductive success and features of congenital <i>B</i>. <i>microti</i> infection in pups of females from experimental groups.</p

Babesiosis in Southeastern, Central and Northeastern Europe: An Emerging and Re-Emerging Tick-Borne Disease of Humans and Animals

There is now considerable evidence that in Europe, babesiosis is an emerging infectious disease, with some of the causative species spreading as a consequence of the increasing range of their tick vector hosts. In this review, we summarize both the historic records and recent findings on the occurrence and incidence of babesiosis in 20 European countries located in southeastern Europe (Bosnia and Herzegovina, Croatia, and Serbia), central Europe (Austria, the Czech Republic, Germany, Hungary, Luxembourg, Poland, Slovakia, Slovenia, and Switzerland), and northern and northeastern Europe (Lithuania, Latvia, Estonia, Iceland, Denmark, Finland, Sweden, and Norway), identified in humans and selected species of domesticated animals (cats, dogs, horses, and cattle). Recorded cases of human babesiosis are still rare, but their number is expected to rise in the coming years. This is because of the widespread and longer seasonal activity of Ixodes ricinus as a result of climate change and because of the more extensive use of better molecular diagnostic methods. Bovine babesiosis has a re-emerging potential because of the likely loss of herd immunity, while canine babesiosis is rapidly expanding in central and northeastern Europe, its occurrence correlating with the rapid, successful expansion of the ornate dog tick (Dermacentor reticulatus) populations in Europe. Taken together, our analysis of the available reports shows clear evidence of an increasing annual incidence of babesiosis across Europe in both humans and animals that is changing in line with similar increases in the incidence of other tick-borne diseases. This situation is of major concern, and we recommend more extensive and frequent, standardized monitoring using a &ldquo;One Health&rdquo; approach