Ten cycling Nigerian West African Dwarf (WAD) ewes were used to determine the effect of Trypanosoma congolense infection on the estrous cycle. The estrus of ewes were synchronized using intravaginal progesterone sponges and divided into 2 groups (A and B) of 5 ewes each after 54 days (3 cycles). The ewes in group A were inoculated with blood containing approximately 5×105 trypanosomes per ml of blood while ewes in group B served as the uninfected control. All the ewes were monitored from infection till the end of the study (56 days). Ewes in the infected group had silent estrus with clinical trypanosomosis that was characterized by undulating parasitemia, intermittent pyrexia, anemia and weight loss. There was no statistical (p > 0.05) difference between the mean estrous cycle length of the infected and the control groups. Estrus behavior of seeking the male, tail wagging, bleating, restlessness, edema of the vulva and mucus discharge from the vulva were observed in both groups at estrus, the basal progesterone profile corresponded with a true estrus rate of 60 % and 90 % for the infected and control groups respectively. However, there were statistical (p < 0.05) differences in the duration and intensity of estrus between the infected and control groups. The study shows that T. congolense infection affects the estrous cycle of Nigerian WAD but not detrimental to cause serious infertility.
Babesia microti is a known zoonotic agent naturally transmitted by Ixodes ticks. Haemaphysalis longicornis, a
widely distributed hard tick in East Asia and Australia, is one of the most important tick vectors of Babesia and
Theileria parasites. Here, we experimentally evaluated the interaction of B. microti parasites and H. longicornis
ticks after blood feeding on mice infected with B. microti. B. microti DNA was detected in engorged larvae and
nymphs after blood feeding on mice infected with B. microti by nested polymerase chain reaction (nested PCR).
In addition, we performed a transmission test of B. microti parasites from H. longicornis ticks to mice. Although,
the transmission of B. microti parasites from H. longicornis ticks to mice was not confirmed, the parasites’ DNA
was detected in engorged nymphs fed on B. microti-free mice. These results indicate that B. microti parasites can
infect to H. longicornis ticks, but the tick not a vector for B. microti parasites.
Methylene blue, the first fully synthetic drug, has been widely used in medical treatments. A few decades ago,
this drug was used as an antimalarial agent. In this study, the in vitro inhibitory effect of methylene blue on
Babesia bovis, B. bigemina, B. caballi, and Theileria equi (B. equi) and the in vivo inhibitory effect on B. microti
were evaluated. Methylene blue significantly inhibited the growth of B. bovis, B. caballi, and T. equi at a 0.1 µM
concentration, while B. bigemina was significantly inhibited at 0.01 µM, on day 3 of cultivation. The half
maximal inhibitory concentrations (IC50) of methylene blue against B. bovis, B. bigemina, B. caballi, and T. equi
were calculated as 0.83±0.02, 0.68±0.09, 0.54±0.14, and 0.49±0.06 µM, respectively. The subsequent viability
assays, in which drug-free media were used for the cultivation, showed that there were no growths of B. bovis or
B. bigemina that had been previously treated with 10 µM methylene blue. Similarly, B. caballi and T. equi that
had been previously treated with 1 µM methylene blue failed to grow in the viability tests. As for the in vivo
inhibition assay, the high dose of methylene blue showed a low inhibitory effect on the in vivo growth of B.
microti at 50 mg/kg body weight treatment groups as compared with the untreated group. Therefore, methylene
blue might not be used for against Babesia and Theileria parasites.
Babesia venatorum, formerly known as Babesia sp. EU1, is a zoonotic hemoprotozoan parasites that
commonly infects deer. In the present study, we investigated B. venatorum infection in Ixodes persulcatus,
an important tick vector capable of transmitting several tick-borne pathogens that cause babesiosis,
encephalitis, tularemia, and Lyme diseases. DNA samples extracted from questing I. persulcatus ticks (n=63)
that had been collected in Selenge province of Mongolia in 2012 and 2013 were screened for B. venatorum
using a nested PCR assay. The findings showed that two of 63 DNA samples were positive for B. venatorum.
The 18S rRNA sequences amplified from B. venatorum-positive DNA samples shared high identity scores
(96.1–99.9%) with known B. venatorum sequences derived from human and tick isolates. In phylogenetic
analysis, the Mongolian 18S rRNA sequences clustered with the previously characterized B. venatorum
sequences. In addition to reporting B. venatorum in Mongolia for the first time, the present study identifies I.
persulcatus as a potential vector of this zoonotic Babesia in Mongolia. Additional studies to investigate the
prevalence of B. venatorum in deer, humans, and ticks in different geographical regions are essential to
understand the epidemiology of this parasite species in Mongolia.
Babesia bovis, a tick-borne hemoprotozoan parasite, causes fatal bovine babesiosis in cattle. Merozoite surface antigens, encoded by msa genes, of B. bovis play an important role in the initial attachment of the merozoite to host erythrocytes. In the present study, B. bovis-positive blood DNA samples (n = 162) sourced from cattle in Thailand were analyzed using type-specific polymerase chain reaction (PCR) assays targeting nine Asian msa-1 genotypes (genotypes C and AS1–AS8). All nine msa-1 genotypes were detected in Thai cattle, and at least one msa-1 genotype was detected in 154 of the 162 samples. The most common genotype was AS7 (n = 139), followed by AS5 (n = 61), AS1 (n = 37), AS8 (n = 32), C (n = 11), AS4 (n = 8), AS3 (n = 5), AS6 (n = 2), and AS2 (n = 1). Co-infection with parasites of different genotypes was also commonly detected, and with 90 (58.4%) of the 154 PCR-positive DNA samples showing infection with more than one genotype. Overall, the detected genetic diversity of msa-1 from B. bovis was much higher than that previously determined in Thailand. These findings warrant further investigation to determine the nature of antigenic variation between the different B. bovis genotypes detected in the cattle population of Thailand.
Fecal samples from 94 Japanese black cattle (5–211 months old) on a farm in Tokachi district, Hokkaido Prefecture, were analyzed, and two calves (6 months old) were positive for Cryptosporidium oocysts (2.1%). The infections seemed to be asymptomatic because the feces were normal. The oocysts were morphologically similar to those of C. andersoni and were confirmed as this species based on the nucleotide sequences of their 18S ribosomal RNA (18S rRNA) genes. Both Type A and B were detected in the 18S rRNA sequences of the positive samples. This is the first report of C. andersoni Type B in Hokkaido Prefecture.
Toxoplasma gondii is one of the most common protozoan parasites globally and requires both a definitive and an intermediate host to complete its life cycle. The population of wild sika deer (Cervus nippon yesoensis) in eastern Hokkaido, Japan, has recently increased and is considered a potential intermediate host of T. gondii. In this study, the seroprevalence of T. gondii infection in 201 wild sika deer from 10 geographical regions in eastern Hokkaido in 2010 and 2011 was analyzed using the latex agglutination test. Antibodies to T. gondii were found in three cases (1.5% of samples), suggesting that deer have started to function as intermediate hosts. This is the first report of seropositivity against T. gondii in wild sika deer in eastern Hokkaido.