Association of Brucellosis with Abortion Prevalence in Humans and Animals in Africa: A Review.
Brucellosis is a zoonosis of both veterinary and public health significance with an economic impact on livestock production in most developing countries (1). This disease, which has a worldwide distribution, is caused by Gram-negative bacteria of the genus Brucella. Currently, there are 11 recognized Brucella species (2), and six of them, are known to be pathogenic for both animals and to humans, namely: B. abortus, B. canis, B. inopinata, B. melitensis, B. pinnipedialis, and B. suis (3). The sources of infection for animals include aborted materials, vaginal discharges, milk and semen from Brucella infected animals. Domestic animals (Cattle, sheep, goats and pigs) are the main reservoirs of Brucella. The transmission of brucellosis to humans occurs through occupational or environmental contact with infected animals or their products (cheese, raw milk and unpasteurized milk) including a travel-association to the disease (4). Person-to-person transmission is extremely rare.
Despite its global distribution, data on the prevalence of brucellosis among humans and animals in Africa is limited. In Africa, the intensive interactions between humans and animals in the ecosystems favor cross-infections in mixed husbandry systems or at the livestock-wildlife interface (5). Brucellosis remains endemic in most areas of the world (6), even if, some of the developed countries have eradicated it from their domestic animal populations. In some parts of Africa, the disease is underreported due to insufficient awareness, inadequate diagnostic protocols, including lack of laboratory reagents (7). In addition, limitations in the implementation of blood testing, milk pasteurization, food hygiene measures, slaughter and heifer vaccination programs, are some of factors which negatively affect the surveillance networks of brucellosis in Africa. However, brucellosis infections in humans can be avoided by applying occupational and food hygiene together with the implementation of bio-security measures in laboratories, while the prevention in animals could be based on good herd management and hygiene strengthened with a careful vaccination program (4).
Brucellosis poses diagnostic and confirmation challenges in humans, domestic and wild animals (8). In humans, brucellosis resembles other febrile diseases such as malaria, and is often misdiagnosed or underreported (9). Even where good laboratory facilities exist, the disease is still misdiagnosed because of the low diseases suspicion levels among the medical practitioners. In some cases, infections due to brucellosis are not necessarily recognized based on clinical evidences because the disease has no pathognomonic signs, and therefore confirmation must be based only on laboratory tests. In livestock industry, the economic impact of brucellosis is mainly attributed to abortions which mostly occur during the last third of pregnancy. In African countries, abortions are followed in some cases by temporary or definitive infertilities also with a decrease or a total absence of milk production (10). Unfortunately, in Brucella infections, the causes of abortions often remain undiagnosed even after a complete necropsy, histopathologic and microbiological examinations (11). Furthermore, there are some limitations on how to make a differential diagnosis with other infectious diseases, making it difficult to assess the real contribution of brucellosis to the observed abortions in humans and in animals. Several studies in Africa have shown an association between seropositivity and abortions (11-13); but in many cases these relationships have been established based on statistical association between prevalence and the history of abortions in herds, not as counter-factual events, which could make an ambiguous interpretation about the role played by brucellosis in the causation of abortions. Furthermore, the presence of organisms does not necessarily indicate a causal association between Brucella and abortions in risk groups, because of several other factors that could bring about abortions. Therefore, the aim of this review was to assess the contribution of brucellosis to abortions observed in humans, domestic and wildlife in Africa, considering the above catalogued shortcomings. For this purpose, the objectives of the review study were: to identify different causes of abortions in humans and animals; to evaluate the impact of abortions in humans and animals and to assess the contribution of brucellosis to abortions observed in humans and animals in Africa.
This literature review was done to demonstrate from published information the contribution of brucellosis to abortions in livestock, humans and wildlife in Africa. Articles in English and French published between 1997 and 2015 were retrieved using large-scale search engines including the Google, Google Scholar, Pubmed, Gopubmed, Freefullpdf and African journals Online. The inclusion criterion was any article in which the authors attributed the responsibility of Brucella infections to abortion occurrence in humans, domestic animals and wildlife in Africa. Articles reporting prevalence of brucellosis in Africa without any association of abortions in humans, domestic and wild animals were excluded. The key words for the search were: [brucellosis, abortion, livestock, Africa]; [brucellosis, abortion, humans, Africa]; [brucellosis, abortion, wildlife, Africa]; [Contribution, brucellosis, abortion, Africa]. For the balanced information, it was necessary to review the Brucella and non- Brucella causes of abortions in humans and animals, as well as their economic impact evaluation without limit only to Africa continent. In this review, the focus was based only on the causes of spontaneous abortions in humans and animals (not induced abortions).
Different causes of abortions in humans and animals
The general causes of spontaneous abortions are due to infectious and non-infectious causes. There are several causes of spontaneous abortions and some of such common causes in humans and animals are discussed below.
Definition of abortion
Spontaneous abortion, or miscarriage, is defined as a pregnancy that ends spontaneously before the fetus has reached a viable gestational time (20th week of gestation) (14). Abortion can be defined also as an expulsion of a dead or living fetus of recognizable size at any stage of gestation. Abortion is also defined as a loss of a fetus which occurs from the moment in which the pregnancy diagnosis is usually performed to the point at which the fetus is considered capable of sustaining life outside the uterus (15). Abortion may be either spontaneous (occurring from natural causes) or induced (artificially or therapeutically). Abortion is most of the time the result of a disturbance in the functioning of the placenta and, it may occur at any stage of pregnancy (16). In case of brucellosis, the presence in uterus of erythritol (a 4-carbon sugar alcohol) is associated with abortions occurrence because it constitutes the placental tropism for the development of Brucella specifically in ruminants (17). This carbon sugar is not found in human uterus or fetus, a reason which makes it more difficult to understand the contribution of Brucella infections to abortions in pregnant women. The pathogenic mechanism for induction of abortion by bacterial and viral infections is not the same depending of the characteristics of each infectious disease which may induce this syndrome (18). Protozoan parasites are common causes of extensive abortion in livestock and some species, including Toxoplasma gondii, Neospora and Sarcocystis, have a two-host life cycle (19). In addition, the pathogenesis of fungal abortions is possibly based on the penetration of fungi and their toxins in the uterus and the fetus by hematogenous route (20). In case of brucellosis, the pathogenesis of abortion is very unclear although, some studies have demonstrated the interactions between brucellosis and the animal trophoblast, which is not the case for the human trophoblast (21).
Causes of abortions in humans
Abnormal chromosomes (translocations) in either partner can cause miscarriage (22). Chromosomal aberrations in parents are a major pre-disposing factor and causative of abortion if carried over to the embryo (23). Generally in Africa, it is rare to diagnose and get service in such cases (24) due to the difficulties in finding trained medical geneticists, genetic counselors and medical scientists. Other causes of abortions may include genetic factors because of lethal gene combinations (25).
In humans, an important cause of early and late abortions is due to an insufficient progesterone (disorders of the luteoplacental progesterone) secretion (26).
Some studies reported the maternal immunologic aberrations to be the cause of repeated abortions (27,28), and the larger numbers of unexplained abortions may have immunological reasons.
Nutritional deficiency and toxic agents
Abortions may also be due to some deficiencies of vitamins, minerals and energy in the body of pregnant females. In terms of maternal health, clinical deficiency (vitamin B12, E) may be a cause of infertility or recurrent spontaneous abortion (29,30). Furthermore, poor iodine tenancy in pregnant woman body has been found in West Africa to be associated to reproductive failure including miscarriage (31). A long exposure to toxic agents such as pesticides may also cause abortions or early embryonic human deaths (32).
Environmental and occupational factors
On rare occasions, an individual may abort after developing a very high fever due to an infection. Spontaneous abortions can be due to environmental factors: for example, the tobacco exposure in some occasions can cause spontaneous abortions (32-34). Occupations; even the income of people (poverty, lifestyle) can in some cases expose them to risk of abortions (32,35).
Causes of abortions in domestic animals
In animals, abortions due to genetic abnormalities occur as an individual case problem rather than as a herd problem. Studies reported abortions and neonatal losses in cattle linked to chromosomal aneuploidy (11,23).
An experimental study reported significant alterations caused by T. brucei in the hypothalamus, adenohypophysis, uterus, placenta and fetal liver with infertility in goats (36). In South Africa, a study reported cases of abortions in Angora goats due to an abnormally low level of adrenal function, coupled with some qualitative changes in adrenal steroid biosynthesis (37).
It has been proved with clinical evidence that using some vaccines in pregnant animals can cause abortions. A study reported an outbreak of abortions following the use of intramuscular infectious bovine virus vaccine in a dairy herd in Canada (38). Abortions which may occur after administration of Leptospira vaccines have also been discussed (39). In case of brucellosis, although the available vaccines RB51 and S19 are effective in controlling brucellosis, studies reported their numerous drawbacks, such as potential to cause abortion in pregnant animals (8,40,41). For Brucella immunization, cattle are vaccinated mostly as heifer calves at 4-12 months of age whereas adult cattle may be vaccinated only in selected high-risk situations.
Nutritional deficiency and toxic agents
Mineral deficiencies were reported in 4% of abortions in goats in California (42). However, a study conducted in South Africa could not associate the observed abortions in Angora goats to nutritional deficiencies (43). Abortions may occur, especially in late gestation if animals are exposed to sufficiently high levels of nitrates in forage (55 % or greater). Experimentally, studies have proved abortions caused by mycotoxins such as zearalenone (44,45) and ergot alkaloids (46).
Some abortions in animals may be a result of an increase in environmental temperature (47), but, evidences are not sufficient to support heat stress as a common cause of abortions.
Abortions caused by infectious diseases in humans and animals
There are a larger number of infectious agents causing abortions in humans and animals and some of them are zoonotic (Table1). In fact, Brucella spp., are among the important bacterial agents associated with abortion during mid-to late gestation including Chlamydia spp., Salmonella spp., Campylobacter spp., Listeria monocytogenes and Coxiella burnetii (8,48,49). In case of Toxoplasma gondii, it used to be misidentified while it is the most probably significant cause of repeated abortion in humans, cattle and dogs (50-52). The evidences are lacking to consider Neospora caninum as a cause of abortions in humans; however, it is one the causative agents of abortions in cattle and dogs (53).
Causes of abortions in wildlife
Toxoplasma gondii infections are suspected to be mostly associated to abortions cases in wildlife (54,55). The Coxiella burnetii and Chlamydiales species have been associated with abortions in wild ruminants (54-57). Some infectious diseases are reported in wildlife such a Rift valley fever (RVF) in Kenya (58), Food and Mouth Disease (FMD) in Zimbabwe (59), tuberculosis in African buffalo in South Africa (60), but little is documented about their association with abortion in wild species in Africa. Serological evidence of brucellosis and abortion were reported in wildlife in USA (61) where B. abortus was isolated for the first time from an aborted female bison (62). In addition, Brucella abortus biovar 1 was isolated from a bison (Bison bison) fetus collected in Yellowstone park (70). In Africa, different studies are reporting on prevalence of brucellosis in wildlife (61,71-73), but little is known about the association of abortions occurrence with infectious diseases including brucellosis in wild species.
Detection of the causes of abortions
The role of infectious agents could be less important if the presence of organisms does not necessarily indicate a causal association with abortion, although the reports indicate 20-30% of their implication in abortions cases diagnosed in laboratories (74). The detection of the causes of abortions in the population may be done by serological assay, immunological, bacteriological and molecular techniques, based on clinical evidences. The seroepidemiological approaches can establish a high degree of association between infections and the abortion level in the farm (75). However, it is difficult to establish that Brucella is a cause of abortion based on serological results only. Furthermore, the gold standard for the diagnosis of brucellosis is isolation and identification of the causative bacterium in a biological containment level three (76). In humans, the history of the patient, the physical examinations, a pelvic ultrasound, the laboratory orientation may be the foundation for a detection of causes of abortions (77).
Management of abortions
In humans, abortions may require expectant management for up to two weeks, and medical therapy which can usually give successful results (78). In animals, vaccination contributes a lot to protection against infectious diseases of public health importance (79). Neosporosis, one of the economically most important causes of abortion in cattle, has prompted researchers to invest in the development of measures to prevent infection of cattle by vaccination (80). However, there are vaccines which may cause abortions in pregnant animals. In case of abortions due to infectious diseases such as brucellosis, a good disposal of aborted materials and culling are required to avoid the human contaminations and the dissemination of infectious agents in the herd.
The impact of abortions in humans and animals
The economic impact of abortions
The economic impact of abortions in animals can be evaluated based on direct costs (value of fetuses lost) and indirect costs: establishing the diagnosis, re-breeding cows that aborted, possible loss of milk yield, and replacement costs if cows that aborted are culled (74). Abortions in domestic animals are of great concern to farmers because the fetus that would form replacement stock is lost and a prolonged period of uterine disease and infertility or sterility may follow leading to unproductive females being maintained for long periods (81). Some loss estimates around US $110.00 for abortions caused by Neospora caninum in a pregnant dairy cow in USA (82). Abortions extend calving interval and increase culling and the economic evaluation from each pregnancy loss was estimated at approximately $2,333 in Korea (83). In Burkina Faso, a study reported an impact of the spontaneous abortion in women of US $56 (27 668 CFA) and underlined the high expenses with short-term economic repercussions on households' poverty (84). In sub-Saharan Africa, very few articles focused exclusively on the cost of treating abortion complications in humans, but authors agreed that it consumes a disproportionate amount of hospital resources (85). In fact, the number of fetus including the milk losses due to abortions in animals are easy to quantify whereas in humans the fetus including the emotion stress associated to abortions are difficult to measure.
Economic impact of abortions due to brucellosis
Higher productivity losses are associated with higher prevalence of brucellosis. Brucella seropositive animals have higher rates of abortion, stillbirth, infertility and calf mortality, as well as reduced growth and longer calving intervals. Often, infected females will abort only once, although they may remain infected their entire life. Studies on the economic production losses of bovine brucellosis are reasonably consistent across a range of production systems in Africa and Asia (13).
In African regions where the infection rate is 30% for bovine brucellosis in breeding females (20% of the herd), the result in economic losses approximate to 5.8% of gross income per animal reared (86). In Mongolia, after estimating the proportion of abortions among brucellosis seropositive animals, a mass vaccination program was implemented with a cost of $8.3 million (87,88). If the costs of the vaccination were shared between the livestock and public health sectors, the intervention may be cost-saving and cost-effective. In Ethiopia, the economic impact of abortions due to brucellosis in camels was estimated to 21% of the total cost (89) while in Sudan it was representing 8.2% of the total losses due to bovine brucellosis (90).
The public health impact of abortions
Aborting animals shed large quantities of infectious agents and pose considerable risk to humans in contact. In some cases, consumers may also be at risk; for example, Coxiella burnetti, responsible for Q-fever, can be excreted in the milk of aborting goats for up to 52 days (91). The disposal of aborted fetuses might be well managed to avoid humans and animal exposure to the pathogen. The human assistance rendered during parturition in abortive cattle, sheep or goat has been associated in some cases to brucellosis infections in humans (92). Some case of abortive animals could result in infection of entire households when animals are kept in close proximity to living accommodation, or when they are brought inside of houses, especially in severe weather (4).
The social impact of abortions
Abortion is a tragic loss and can be associated with significant psychological problems for women, their partners and families in general. For women who get an experience of spontaneous abortion, it is a stressful event as well as they are not sure to conceive and arrive at term successfully with the next pregnancies. About 1% of couples will experience recurrent spontaneous abortion (93). In animals, abortions can lead to nutrition insecurity because of the decrease of milk production and loss of calves. In addition, infectious diseases which lead to abortions can unable livestock producers to meet their social obligations such as the man's position, influence and the respect in the community as well as the payment of children school fees, medication, clothes (110,111).
The contribution of brucellosis to abortions observed in humans and animals in Africa
Some studies in this review (5/18) reported data on the abortion associated with brucellosis in Africa (96,100). These estimates of abortions reported in this review are high (0.17-16.2%) compared to the normal abortion rate, which is ranged between 2-5% in cattle (86). Domenech et al. (112) demonstrated, using a formula, the existence of correlation between the manifestation of brucellosis symptoms and the increases of abortion cases in African cattle. Some authors have also reported the association between brucellosis and abortions observed in Africa based on the calculated odds ratio (101,103).
However, some abortions recorded in Africa may be due to co-infections between brucellosis and others infectious diseases (95,100). Differential diagnosis of brucellosis with others abortive infections prevalent in the study area could reveal the true association between the observed abortions and the prevalence of each disease.
Brucellosis is one of the major zoonotic diseases on the African continent and has an economic impact on livestock productivity (abortions, decrease of milk production). The syndrome of abortion affects the household's income and constitutes a risk factor for the dissemination of Brucella in humans and animals. A review of online literature has been done with an objective of assessing the contribution of brucellosis to abortions in humans, domestic animals and wildlife in Africa. The association may exist between brucellosis and abortions in animals which manifest clinical symptoms for this disease in Africa (12), and a correlation exists between the manifestation of brucellosis symptoms and the increases of abortion cases in African cattle (86). Some events at farm or risk group level such as exposure to aborted materials, unpasteurized milk consumption, artificial insemination, could be recorded during follow up for completing the differential diagnosis with other prevalent infectious diseases related to abortions. The high prevalence of brucellosis in cattle reported in Africa is most of time associated with abortions (13); around one fifth of cows may abort where seroprevalence is higher than 30%.
Actually, studies on the seroepidemiology of brucellosis in Africa are reported with an improvement in the sample size calculation and sampling methods, the diagnostic methods, the ethical considerations (98,101,113). However, in this review the sample size and type varied from studies, species and regions in Africa (Tables 2 and 3). This could be because brucellosis is a herd level disease: an occurrence of abortion in risk groups is enough to start investigation. Otherwise, the large sample size and appropriate sampling method is very important to determine the association between brucellosis and observed abortions. Methods used for the diagnosis of brucellosis in the reviewed papers include: RBPT, ELISA, MRT, SAT, culture, identification and molecular characterization of Brucella species (Figure1). The serologic methods are the most used in Africa to determine the role played by brucellosis in abortions even if these tests are known to be less specific, and the results can be biased with false positive because of some cross-reactions with other bacteria. However, the contribution of brucellosis to abortions is less highlighted by molecular techniques (114,115), although this disease is considered to be one of the major causes of abortions in cattle in Africa (109,116). In this review, Brucella abortus seemed to be the specie most associated with abortions in Africa (12,99,102,109). Generally, the cost of molecular techniques could be a challenge to African countries. However, this technique could be a good way to detect the presence of infectious agents in aborted materials and to assess the real contribution of brucellosis in abortions recorded in humans and animals on the continent. Molecular epidemiology could contribute as a tool for identification and characterization of Brucella species from aborted animals, determining their origin and possible spillover to other species (especially wildlife). Studies could extend their exploration to the presence of Brucella in the human aborted materials or breast milk after abortions, this will complete data on seroprevalence studies and questionnaire surveys in Africa.
In this review, studies reported abortions associated with brucellosis in Africa, focusing much on domestic animals (94,98,103) and less in humans (Tables 2 and 3). Although some authors reported the association between brucellosis and the observed abortions in humans in Africa (97,101,104,106), the pathogenesis of brucellosis in pregnant women still remains to be elucidated. However, the abortion process is well described in animals due to the role played by erythritol (sugar), which may confer the tropism for Brucella development in the uterus. Nevertheless, out of Africa, it has been suggested that brucellosis may cause higher rate of abortions, more frequently than do other bacterial infections in pregnant women (115). Furthermore, in situations where brucellosis is suspected to be a cause of abortions in pregnant women, laboratory analyses are required to confirm the role played by others febrile diseases (such as malaria) or abortive infectious diseases (Rift valley fever, Toxoplasmosis) which are equally prevalent in Africa. The clinical symptoms observed in pregnant women could complete the differential diagnosis with the prevalent others abortive and febrile diseases. Furthermore, this gap can be rectified by applying for the confirmation of the brucellosis in humans based on isolation and molecular techniques.
Generally, no evidence of abortion due to this disease has been documented in wildlife; despite the findings from a single study that reported the impact of brucellosis on abortions in the wildlife-livestock interface (103). In Africa, interactions are observed between domestic and wild animal species in pastoral farming systems where they may be exposed to aborted materials, when sharing the same pasture or common source of water. Furthermore, smallholder farmers might be affected by the abortions exposure due to brucellosis because of the cut and carry as feeding system (117).
Eighteen papers were used to extract data because they reported on the role played by Brucella infections on abortions observed in animals and humans in Africa (Tables 2 and 3). However, the quality of this review could have been affected by the lack of assessment of bias in the studies, the non-inclusion of statistical management of data, also with the restriction of the study area only to Africa. Nevertheless, these limitations may be avoided by a systematic review (instead of a review) if published data on the contribution of brucellosis to abortions in humans and animals in Africa could have been found with a significant number of papers. Most of the studies reviewed were cross-sectional in design (Figure1). Despite of their time consuming, the loss of subjects (attrition) and the limitations of budgets for research, case control and longitudinal studies could reflect possibly good observations with clinical evidence during the assessment of the contribution of brucellosis to abortions in Africa.
Brucellosis is reported in Africa with high prevalence in humans and animals. However, there is limited published data about the contribution of this zoonotic disease to abortions in humans and animals. The literature reviewed stated little about the estimation of the abortion rate and the calculated odds ratio which are strong indications of association between brucellosis and abortions in humans and animals in Africa. More data are reported by eastern and southern parts of Africa on the assessments of the contribution of brucellosis to abortions, but generally in Africa, there is a lack of a rigorous sample size calculation, an inadequate study design planning, and ethical clearance considerations are also required. The identification of the causes of abortions in Africa, specifically the role played by brucellosis, is based on routine test (RBT) and immunological diagnosis (ELISA); but, the detection should be based on more definitive methods such as isolation and molecular characterization from blood, milk and aborted materials. Furthermore, little is reported about the association of brucellosis to abortions in humans (five papers out of 18). As the causes of abortions are multiple, the clinical observations in humans and animals could complete the differential diagnosis with the prevalent abortive diseases. In addition, the contribution of brucellosis to abortions in wildlife in Africa is not elucidated in the literature, and, the economic impact evaluation of abortions in the herds due to this disease remains to be completed. The epidemiologic approach based on collecting core data concerning both aborted and non-aborted individuals (humans and animals) could determine the contribution of brucellosis to abortions in populations and could help to monitor the prophylaxis in humans and the progress of vaccination programs in animals. Due to the strong interactions in the human-livestock-wildlife interface in Africa, the contribution of brucellosis to abortions calls for the interdisciplinary collaboration for its understanding and controlling.
We would like to thank the Intra-ACP Academic Mobility Scheme through Grant Agreement 2012-3166 to Sokoine University of Agriculture for the financial support of this review.
Contribution of Authors
The first and the fourth authors prepared the manuscript for publication. All the authors mentioned in the article reviewed the final version and they approved the manuscript.
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Jean-Bosco Ntirandekura (1*), Lucas Eliaimringi Matemba (2), Sharadhuli Iddi Kimera (1), John Bwalya Muma (3) and Esron Daniel Karimuribo (1)
Sokoine University of Agriculture, College of Veterinary and Biomedical Sciences, Department of Veterinary Medicine and Public Health, Morogoro, Tanzania (1); National Institute for Medical Research, Morogoro, Tanzania (2); University of Zambia, School of Veterinary Medicine, Department of Disease Control, Lusaka, Zambia (3)
(*) For Correspondence: Email: firstname.lastname@example.org; Phone: +255 742601303
Table 1: Infectious agents which can cause abortions in humans and animals Host Bacteria Virus Staphylococcus aureus, human Ureaplasma immunodeficiency Humans only urealyticum Virus Mycoplasma hominis Dengue virus Treponema pallidum Influenza virus Herpes simplex virus Brucella Humans and Leptospira Salmonella Animals Listeria Campylobacter (vibrio) Phlebovirus Arcanobactericium Aphthovirus (Actinomyces) Bovine herpes virus-1 Animals Escherichia coli Equine herpes virus-1 (domestic and Streptococcus Bovine viral diarrhea wildlife) Zooepidemicus Border disease Rhodococcus equi Mycoviruses Leptospiras interrogans Bluetongue Parvovirus Suid herpisvirus 1 Equine viral arteritis Host Fungi Protozoans References Plasmodium (18,63,64) Humans only Toxoplasma gondii (48,51,62,65,66) Humans and Chlamydia Animals Mycoplasma Aspergillus Neospora caninum (12,44,48-50,52,54,58,) Mucor Trichomona fetus (67-69) Candida Coxiella (Q fever) Animals Coccidia (domestic and Babesia wildlife) Trypanosomum equiperdum Table 2: Papers reviewed per region and species on the contribution of brucellosis to abortions in Africa Region Countries Humans Dom. Humans & Animals dom. animals North Africa Morocco, Egypt, 1 3 0 Tunisia West Africa Nigeria, Niger 0 3 0 Central Africa Cameroon, Chad 0 1 0 East Africa Tanzania, Kenya, 1 3 2 Rwanda, Ethiopia Southern Africa Zimbabwe, 1 3 0 Zambia, South Africa Region Wildlife Total References North Africa 0 4 (94-97) West Africa 0 3 (12,98,99) Central Africa 0 1 (86) East Africa 0 6 (100-105) Southern Africa 0 4 (106-109) Table 3: Data extracted from literature on the contribution of brucellosis to abortions observed in Africa Studies/ Study design Sample size Samples species type Case-control 324 women Blood Cross- 129 women Blood Humans sectional Prospective 125 women Blood, swabs Humans and Cross- 60 women, 27 Blood domestic sectional cattle animals Cross- 483 cattle, 120 Blood sectional humans Cross- 20 herds (214 blood, sectional cattle) swabs, milk Cross- 23 sheep Blood sectional Cross- 5192 cattle (681 Blood, sectional herds) hygromas Domestic fluids) animals Cross- 24 cattle Blood sectional Cross- 700 cattle Blood, milk sectional Cross- 200 cattle, 50 Blood, sectional goats, 35 sheep milk, aborted materials Cross- 283 cattle, Blood, sectional 756camels, 757 goats Cross- 886 cattle Blood sectional Cross- 239 cattle Blood sectional Cross- 28 sheep Milk sectional blood, vaginal swab Cross- 22 sheep Milk sectional Cross- 260 cattle Blood sectional Cross- 10 cattle, 5 Blood sectional buffalo, 9 goats,1 sheep Studies/ Diagnostic methods Prevalence Ethical species issues SAT 26.8% Yes SAT 38.8% Yes Humans NR 4% NR Humans and RBPT 25% Yes domestic animals RBPT, ELISA 0 - 28.95% Yes RBPT, culture, RT-PCR 31.3% Yes 4.34% NR ELISA, MLVA-VNTR Herd:11.2- 17.2% Yes Individ: 1.3% Domestic animals RBPT 15.4 - 85% NR RBPT, culture, ELISA, 6.7 - 9% Yes PCR RBPT, ELISA, MRT, 48% Yes culture, PCR, MLVA-VNTR RBPT, CFT Cattle : 10.6% Yes camel : 2.2% goats : 1.9% RBPT, ELISA 23.9% NR RBPT, SAT, CFT, 3.8 RBPT, SAT, MRT, 14.3% NR culture RBPT, SAT, MRT, 14.5% NR Culture ELISA 16.8% NR RT-PCR -cattle: 100%; NR -buffaloes: 50%; -goats:33.3%; -ewe:100% Studies/ Abortion (OR) References species rate NR 2.3 (101) NR NR (97) Humans NR NR (106) Humans and NR NR (104) domestic animals NR NR (105) NR NR (95) 7% NR (96) No 3.0 (12) Domestic animals 0.17- 11.8 NR (86) NR NR (107) NR NR (102) Camels: cattle: (103) 23.4% cattle: 4.7 13.8% goats goats: 6 12.4% 9 camel: 1 Herd: 3.4 (108) 50% Individ: 16.2% NR NR (109) NR NR (98) NR NR (99) 6.5% 0.7 (100) 1.1 NR NR (94)
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|Author:||Ntirandekura, Jean-Bosco; Matemba, Lucas Eliaimringi; Kimera, Sharadhuli Iddi; Muma, John Bwalya; Ka|
|Publication:||African Journal of Reproductive Health|
|Date:||Sep 1, 2018|
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