Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 July 2020 | 12(10): 16245–16250
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5466.12.10.16245-16250
#5466 | Received 14 October 2019 | Final
received 06 July 2020 | Finally accepted 10 July 2020
Detection of hemoparasites
in bats, Bangladesh
Shariful Islam 1 , Rakib Uddin
Ahmed 2, Md. Kaisar Rahman 3, Jinnat Ferdous 4, Md. Helal
Uddin 5,
Sazeda Akter
6, Abdullah Al Faruq 7, Mohammad Mahmudul
Hassan 8, Ausraful Islam 9 &
Ariful Islam 10
1, 3,4Institute of Epidemiology,
Disease Control and Research (IEDCR), Mohakhali, Dhaka 1212, Bangladesh.
1,3,4,10EcoHealth Alliance, New York, NY 10018,
USA.
2,5,6,7,8Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Khulshi, Chattogram 4225,
Bangladesh.
9International Centre for
Diarrhoeal Disease Research, Bangladesh (icddr,b),
Mohakhali, Dhaka 1212, Bangladesh.
1Sharifdvm51@gmail.com, 2rakibcvasu@gmail.com,
3kaisar.kaif@gmail.com, 4ferdousjinnat90@gmail.com, 5helal.cvasu43@gmail.com,
6najatdvm@gmail.com, 7faruqabdullahal103@gmail.com, 8miladhasan@yahoo.com,
9islam_ausraf@icddrb.org,
10arif@ecohealthalliance.org (corresponding
author)
Editor: Bahar S. Baviskar,
Wild-CER Society for Wildlife Conservation, Nagpur, India. Date
of publication: 26 July 2020 (online & print)
Citation: Islam, S., R.U. Ahmed, M.K.
Rahman, J. Ferdous, M.H. Uddin, S. Akter, A.A. Faruq,
M.M. Hassan, A. Islam & A. Islam (2020). Detection of hemoparasites in bats,
Bangladesh. Journal of Threatened Taxa 12(10): 16245–16250. https://doi.org/10.11609/jott.5466.12.10.16245-16250
Copyright: © Islam et al. 2020. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: The present study
was supported by USAID PREDICT project (cooperatve
agreement number GHN-A-OO-09-00010-00) and Chattogram Veterinary and Animal Sciences University.
Competing interests: The authors
declare no competing interests.
Author details: Shariful Islam, wildlife veterinarian and
epidemiologist, interested in zoonotic infectious diseases at human-animal
interface; Rakib Uddin Ahmed, veterinary microbiologist; interested in animal diseases;
Md. Kaisar Rahman, wildlife researcher and
epidemiologist, interested in antimicrobial resistance and zoonotic diseases; Jinnat Ferdous, veterinary epidemiologist, interested in
economic impact of zoonotic diseases;
Md. Helal Uddin, veterinary epidemiologist,
interested in animal welfare and conservation of wildlife and infectious
disease research in one health approach; Sazeda Akter, veterinarian and academician, interested in economic
diseases of farm animals; Abdullah Al Faruq, veterinarian and academician,
interested on molecular study of animal diseases; Mohammad Mahmudul
Hassan, professor and epidemiologist, interests in epidemiology and ecology of
infectious diseases in one health
approach; Ausraful
Islam, scientist, interested in epidemiology of infectious diseases, Emerging
zoonotic pathogens and One Health and Ariful Islam,
veterinary epidemiologist and disease ecologist, interested in understanding
zoonotic infectious disease emergence, their ecology and evolution at animal-
human-environment interface.
Author contribution: Conceptualization, validation,
project administration, investigation and supervision: AI and AI; Methodology and data curation:
RUA, MKR, MHU, SA, AAF, AI & AI; Formal analysis: SI & JF;
Writing—Original draft: SI & JF; Writing—Review & editing: SI, JF, MMH
& AI. All authors have read and agreed to the published version of the
manuscript.
Acknowledgements: This study was made possible by
the support of the American people through the United States Agency for International
Development (USAID) Emerging Pandemic Threats PREDICT project (cooperative
agreement number GHN-A-OO-09-00010-00).
We thank the Bangladesh Forest Department and the Ministry of
Environment and Forest for permission to conduct this study. We are also grateful to International Centre
for Diarrhoeal Disease Research, Bangladesh (icddr,b),
and its core donor, the Governments of Australia, Bangladesh, Canada, Sweden,
and the UK for providing unrestricted support to icddr,b. We thanks to Peter Daszak,
Jonathan H. Epstein, Kevin J. Olival, Melinda K. Rostal, Emily S. Gurley, Najmul
Haider, Tapan Kumar Dey,
Abdul Hai, Pitu Biswas, and Gafur
Sheikh for their contributions to this study.
Abstract: A cross sectional study was
conducted (2010–2013) to determine the diversity of hemoprotozoa
among bats of Bangladesh. Microscopic
examination of blood smears (N=533; Pteropus
medius (377), Rousettus leschenaultii
(111), Megaderma lyra
(45))
revealed 9% of bats (95% confidence interval CI: 7–12%) were positive for hemoprotozoa. The
overall prevalence of hemoparasites among P. medius was 5% (n=20, 95% CI: 3–8%); where Babesia sp. was 3% (n=12, 95% CI: 2–5%) and Hepatocytis sp. was 2% (n=8, 95% CI:
1–4%). Moreover, 13% of R. leschenaultii
were positive
(n=14, 95% CI: 7–20%) where prevalence of Babesia sp. was 10% (n=11, 95% CI: 5–17%) and
prevalence of Hepatocystis sp. was
3% (n=3, 95% CI: 1–8%). Twenty-nine
percent (n=13, 95% CI: 16–44%) of M. lyra harbored
hemoparasites, among which 20% (n=9, 95% CI: 10–35%)
were Babesia sp. and 9% (n=4, 95% CI: 2–21%) were
Hepatocystis sp. The study indicates bats remain important
hosts for various zoonotic parasites and suggests further research.
Keywords: Babesia, Bangladesh, Bat, Hemoprotozoa,
Hepatocystis, prevalence.
INTRODUCTION
Bats, classified
under the order Chiroptera, have long been postulated
to play an
important role in arthropod
suppression, seed dispersal, and pollination. The rich diversity in bat dietary habits assists in maintaining ecosystem
health. In Bangladesh, 31 bat species
are found, three of which
are fruit-eating.
Of all frugivorous
bats, Pteropus medius and Rousettus leschenaultii are common and widely distributed in the country. The False Vampire Bat Megaderma lyra, largest
of insectivorous bats, is also
quite common and widespread in Bangladesh (Khan 2001).
Bats are associated
with zoonotic transmission
of coronaviruses including
severe acute respiratory syndrome
coronavirus-2 (SARS-CoV-2), middle-east respiratory syndrome coronavirus
(MERS-CoV), Ebola, Nipah, and Hendra
viruses (Calisher et al.
2006; Zhang & Holmes 2020), as well as malaria-causing protozoa like Plasmodium sp.,
Hepatocystis, Nycteria,
and Polychromophilus
(Schaer et al. 2013). Among nine hemosporidian genera, Hepatocystis infects a wide
range of hosts including primates, bats, ungulates, and rodents, in addition to Plasmodium (Manwell & Kuntz 1966). Parasites of seven other hemosporidian genera, however, have been found exclusively
in bats, emphasizing that they might harbor
the most diverse set of hemosporidian
parasites within the mammalian clade. The prevalence of hemosporidian parasites among
fruit and insectivorous
bats has been detected previously
to be 40% (Schaer et al. 2013).
Hepatocystis sp.
was identified from a
species of flying fox, P. hypomelanus
(Olival et al. 2007), displaying
an unusually high diversity and is also prevalent in Epauletted
Fruit Bats Epomophorus wahlbergi (Schaer
et al. 2013).
In light of these findings, bats have been identified
as possible reservoirs of hemoprotozoa. They are included in epidemiological surveys, and particularly
for the detection
of bat-specific blood
protozoa. Due to the gross
destruction of habitat with
rapid urbanization, contact
between human and bats is showing an increasing
trend. Frugivorous
bats usually suck the juice of fruits
instead of eating the whole fruits. They may play an
important role in the
transmission of infectious agents
to rural communities, particularly small children, who collect those bat-wasted fruits (Rahman et al. 2012). In addition, ectoparasites which feed on hemoprotozoa-infected bats, could
serve as a route of transmission to humans. The potential public health threats posed by bats thus
suggests the importance of studying hemoprotozoa towards its proper control and better management of human diseases
related to bats. Maximum research has led on emerging viruses in bats; however, bacterial and parasitic agents
in bats have been least studied
and most neglected. For a better understanding of parasitic pathogens in bats, we conducted this study to
identify the hemoparasites of bats in Bangladesh.
MATERIALS AND METHODS
As part of a larger
study through the United States Agency for International Development (USAID) Emerging
Pandemic Threats PREDICT
project and associated Ecology of Nipah virus survey, we captured
bats in seven districts within or near human settlements across Bangladesh (Figure 1). A total of 533 (P. medius 377, R. leschenaultii 111, M. lyra 45) blood samples were collected randomly from bats during 2010 and 2013. The methods of bat sampling, species identification;
age, weight, sex, physiological, and reproductive status determination were done based on PREDICT One Health Consortium (2017) and Epstein et al. (2008).
The bats were released
immediately after sample collection.
Blood smears were
stained with Romanowsky-Giemsa solution (working
solution) for 25–30 minutes, examined
by an Olympus BX61 light
microscope (Olympus, Shinjuku Monolith,
2-3-1 Nishi-Shinjuku, Shinjuku-ku,
Tokyo 163-0914, Japan) equipped with
Olympus DP70 digital camera (Olympus, Tokyo, Japan) and
imaging software AnalySIS FIVE (Olympus, Tokyo
Japan). A skilled
parasitologist examined one blood film from each bat. Approximately 100 fields were examined at low magnification
(400), and then at least 100 fields were studied at high magnification
(1,000). In total,
the approximate number of screened red blood cells was 5×105 for each blood
film. The intensity of infection
was estimated as a percentage by
counting the number of parasites per 10,000 erythrocytes
examined, as recommended (Godfrey et al. 1987).
Parasites were identified
using previously published works (Marinkelle 1996; Olival et al.
2007). The data were
recorded in MS Excel-2007 (Microsoft Corporation,
Redmond, WA 98052-6399 USA) and transferred
to the STATA/IC-13.0
software (StataCorp, 4905, Lakeway
Drive, College Station, Texas 77845, USA).
RESULTS
Nine percent (n=47; 95% CI: 6.6-11.6%)
of the total sample was
found to be positive for hemoprotozoa. The overall prevalence
of hemoprotozoa was 5%, 13%, and
29%, respectively in P. medius (n=20, 95% CI:
3–8), R. leschenaultii (n=14, 95%CI: 7–20), and M. lyra (n=13, 95%CI: 16–44).
In P. medius, Babesia sp. was found at the same percentage in both sexes (3%), Hepatocystis sp. was found
higher in females
(3%). The prevalence
of Babesia sp. was higher in adults (4%) while Hepatocystis sp. prevalence was higher in neonates (6%). Both Babesia
sp. (4%) and Hepatocystis sp. (3%) prevalence were higher in peri-urban area compared to rural
settings (Table 1). In M. lyra, male were
more infected (25%) by Babesia sp. than females (16%) whereas Hepatocystis sp. infection was higher in females (12%) than in males (5%). On the other hand, Babesia sp. infection is more prevalent
in adult M. lyra (20%) and bats of rural areas (20%) than Hepatocystis sp. (9%) (Table 1). In case of R. leschenaultii,
Babesia sp. infection was higher in males (13%) than in females (6%) but Hepatocystis
sp. was found to be at higher percentage in females (4%) than males (2%). Juveniles were more prone to Babesia
sp. (13%) than adult bats
(8%). No Hepatocystis sp.
infection was found in juveniles. In rural areas, Babesia sp. infection was more frequent
(10%) than Hepatocystis
sp. (2.7%). No
associations, however, were found to be
statistically significant (Table
1).
DISCUSSION
To the authors’ knowledge, this is the first study to report the prevalence of hemoprotozoa in bats of Bangladesh. The study
identified Babesia sp. and Hepatocystis sp.
in three different bat species (Figure 2). The identified hemoparasites in bats
are similar to other reports from
bats globally (Hornok et
al. 2015; Manwell & Kuntz
1966; Marinkelle 1996; Olival
et al. 2007; Schaer et al. 2015, 2017). Bats have harbored a
diverse set of hemosporidian species for centuries (Schaer et al. 2013) and Hepatocystis was found to be at a high endemic level in Pteropodidae (Schaer et al.
2017). Although
the identified parasite
species have not been associated
with public health implications,
there is evidence of co-infection of primates and crossing of the primate barrier by Hepatocystis sp. (Thurber et al. 2013). Furthermore, some of the hemosporidian
species from bats resemble rodent mammalian
parasites (Schaer et al. 2013). The potential for bat-human, bat-rodent-human, and bat-arthropod-human
cross-species transmission of hemoprotozoa is not known but warrants further investigation, particularly as the bat species included in the study are native to Bangladesh and share habitat as well as food and
water sources with humans, suggesting potential plausible routes of accidental
transmission.
The overall prevalence
of blood protozoa (9%) was lower
than that of earlier reports from various countries
(Nartey 2015; Schaer et al.
2013). Hemoparasites
in bats can be found as a result of feeding habits (e.g., feeding on insect vectors from which
they may acquire the hemoprotozoa). The prevalence of B. canis in bats was reported
as 2.7% by Hornok et
al. (2015) which is much lower than the
present study.
Other studies reported
50% (Gardner & Molyneux 1987) and
23% (Lord 2010) prevalence of Babesia
sp. in bats.
Most of the previous
studies identified B. vesperuginis
(Gardner & Molyneux
1987; Marinkelle 1996; Lord 2010) in bat species throughout
the world. The role of bats in
the ecology of Babesia sp. and the vectors
involved in transmission of Babesia
sp. among them warrants further investigation. In the present study, the protozoa were identified up to the level of genus. Hepatocystis
sp. prevalence was lower in this study
than in a previous study in Malaysia (Olival et al.
2007). These findings,
however, may vary due to
the study area, duration of the study, resistance of bats and lack of bat fly vectors in Bangladesh.
Infection with Babesia sp.
was higher in males (M. lyra and R. leschenaultii)
whereas in case of Hepatocystis sp. the
prevalence was higher for females. These
differences can be attributed to variation in behavior,
feed composition, and body mass between sexes (Wilson et al. 2002). Besides, sex hormone, testosterone increase
the susceptibility to parasitism (Wilson et al. 2002). Moreover, parasite development and
transmission is favored by the colonial habits of
females (Christe et al. 2000). Adult P. medius
had higher Babesia percentage than juvenile, may be due to increased
growing host age. Young animals are less
susceptible to Babesia due to inverse age resistance (Christensson 1989). But
the same hemoparasite was higher in juvenile R. leschenaultii which can be attributable to the ability
of the parasite’s vertical transmission.
Hepatocystis was higher in juvenile P.
medius, because they have low body mass, naive
immune system, and nearly no anti-parasite behavior. The pattern of parasitism in bats, however,
should be explored in-depth in future studies.
CONCLUSION
We report a survey of hemoparasites in bats undertaken
over three consecutive years at habitat fragmented
landscape in human settlements areas
in Bangladesh, where the prevalence and diversity of bat-infecting hemosporidian parasites have not
been studied before. Molecular screening
should be undertaken in future to overlay data in the microscopy with those from
molecular biology. Molecular characterization is the only way to definitively
confirm the species of a hemoparasite. The findings, however, remain of great interest. Further studies are
needed to determine the species of
parasites harbored in bats of Bangladesh.
Table 1. Prevalence of hemoparasites in 03 bat species (N=533) from Bangladesh
(2010–2013).
Bat species |
Variables (n) |
Babesia % (n) |
95% CI |
Hepatocystis % (n) |
95% CI |
P. medius |
Male (211) |
3 (7) |
1.3–6.7 |
1.4 (3) |
0.3–4.1 |
Female (166) |
3 (5) |
0.9–6.8 |
3 (5) |
0.99–6.9 |
|
Adult (199) |
4 (8) |
1.8–7.8 |
1 (2) |
0.1–3.6 |
|
Sub-adult (143) |
2 (3) |
0.4–6.0 |
3 (4) |
0.8–7.0 |
|
Juvenile (35) |
3 (1) |
0.07–14.9 |
6 (2) |
0.7–19.2 |
|
Peri-urban (237) |
4 (10) |
2.0–7.6 |
3 (6) |
0.9–5.4 |
|
Rural (140) |
1 (2) |
0.2–5.1 |
1 (2) |
0.2–5.1 |
|
Sub-total |
377 |
3 (12) |
1.7–5.5 |
2 (8) |
0.9–4.1 |
M. lyra |
Male (20) |
25 (5) |
8.7–49.1 |
5 (1) |
0.1–24.9 |
Female (25) |
16 (4) |
4.5–36.1 |
12 (3) |
2.6–31.2 |
|
Adult (45) |
20 (9) |
9.6–34.6 |
9 (4) |
2.5–21.2 |
|
Rural (45) |
20 (9) |
9.6–34.6 |
9 (4) |
2.5–21.2 |
|
Sub-total |
45 |
20 (9) |
9.6–34.6 |
9 (4) |
2.5–21.2 |
R. leschenaultii |
Male (62) |
12.9 (8) |
5.7–23.9 |
2 (1) |
0.04–8.7 |
Female (49) |
6.1 (3) |
1.3–16.9 |
4 (2) |
0.5–14.0 |
|
Adult (103) |
9.7 (10) |
4.8–17.1 |
3 (3) |
0.6–8.3 |
|
Juvenile (8) |
12.5 (1) |
0.3–52.7 |
- |
- |
|
Rural (111) |
9.9 (11) |
5.1–17.0 |
3 (3) |
0.6–7.7 |
|
Sub-total |
111 |
9.9 (11) |
5.1–17.0 |
3 (3) |
0.6–7.7 |
Total (N) |
533 |
6.0 (32) |
4.1–8.4 |
3 (15) |
1.6–4.6 |
For
figure & image - - click here
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