| 1. |
- Aželytė, Justė, et al.
(författare)
-
A comparative analysis of the dynamics of Plasmodium relictum (GRW4) development in the blood during single and co-infections
- 2022
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X. ; 226
-
Tidskriftsartikel (refereegranskat)abstract
- Although co-infections and interactions of parasites are a very common phenomenon in the wild, information received from studies on avian Plasmodium spp. is scarce and fragmented due to its complex nature. Different interactions of parasites and domination of one parasite may have a detrimental effect on transmission success of another pathogen. Untangling these interactions and competitive behavior of malarial parasites may help understanding why some haemosporidian parasites are dominant in certain host species, while others are observed only occasionally. We investigated the development of Plasmodium relictum (genetic lineage GRW4) during single and co-infection with a closely related lineage SGS1, with the aim to determine whether co-infections affect parasite development and condition of experimentally infected Eurasian siskins (Spinus spinus). For the experimental study of these two closely related lineages, a new qPCR protocol was designed to accurately quantify the parasitemia, i.e. the amount of infected red blood cells, during the blood stages of each of the lineages. Our results show that during co-infection, GRW4 parasitemia was transient and disappeared from peripheral blood during acute increases of SGS1. Health parameters of infected birds did not differ between the GRW4 single infected group and the co-infection group. GRW4 induced infection was outcompeted and suppressed by the presence of the lineage SGS1, which is broadly transmitted in Northern Europe. This suggests that double infections and dominating lineages in the area may influence the transmission success of some avian Plasmodium parasites.
|
|
| 2. |
- Ciloglu, Arif, et al.
(författare)
-
Prevalence and genetic diversity of avian haemosporidian parasites at an intersection point of bird migration routes : Sultan Marshes National Park, Turkey
- 2020
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X. ; 210
-
Tidskriftsartikel (refereegranskat)abstract
- Avian haemosporidians (Haemosporida) represent a globally distributed, species-rich multiparasite-multihost host-parasite system. Each year, many of these parasite lineages are carried between temperate and tropical regions by migratory birds. While several factors can limit the transmission of avian haemosporidians to new areas, recent studies have shown that some abundant parasites can sometimes disperse and be transmitted in new areas to become emerging infectious diseases. In this study, we investigated the prevalence and diversity of avian haemosporidian parasites in Sultan Marshes National Park (SMNP), a major stopover site in the eastern Mediterranean flyway, and we evaluated the potential for avian haemosporidians in SMNP to be transmitted to areas outside of their known distributions. We sampled a total of 565 migratory and resident birds belonging to 39 species and 23 families. We applied both molecular and microscopic methods to detect and identify avian haemosporidian infections and also quantified the frequency of potential abortive infections. We identified a total of 52 different mitochondrial cytochrome b (cyt b) parasite lineages belonging to the genera Plasmodium (N = 12), Haemoproteus (N = 31), and Leucocytozoon (N = 9) in 193 (34.2%) infected birds. Ten of the lineages were reported for the first time. Our findings show that numerous parasite lineages are actively transmitted among resident bird species of SMNP. Our findings also revealed new parasite-host interactions while considering the role of possible abortive infections. The relatively high frequency of presumed abortive infections suggests that analyses of datasets generated only by PCR-based methods should be interpreted with caution. We also compared the prevalence and distribution of avian haemosporidian infections in both resident and migratory bird species and showed that haemosporidian prevalence was related to bird migratory behavior. The results of this study contribute to a better understanding of the ecological and genetic adaptations associated with changes in transmission areas of avian haemosporidian parasites.
|
|
| 3. |
- Irum, S., et al.
(författare)
-
Cutaneous Leishmaniasis (CL) : A Cross-Sectional Community Based Survey on Knowledge, Attitude and Practices in a Highly Endemic Area of Waziristan (KPK Province), Pakistan
- 2021
-
Ingår i: Acta Tropica. - : Elsevier. - 0001-706X .- 1873-6254. ; 213
-
Tidskriftsartikel (refereegranskat)abstract
- Recent outbreaks of Cutaneous Leishmaniasis (CL) in Waziristan make the disease a public health concern in Khyber Pakhtunkhwa (KPK) province, Pakistan. The awareness and behavior of local community towards the disease is an important factor towards effective control and management of CL in endemic areas of Pakistan. A cross-sectional community based survey was piloted in new emerging district of North Waziristan Agency (KPK province), Pakistan from August 2019- February 2020. The study aimed to examine the Knowledge, Attitude and Practices (KAP) of the local community members regarding CL. The results revealed that majority of the participants were male. Only 48.2% participants have knowledge about CL and the respondents had a moderate knowledge of CL vector and the disease. Few of the respondents were aware that CL is caused by sand flies, their breeding place, biting time, transmission of CL and control measures. Skin infection and sand-flies were the main disease symptoms and disease vector were known to some of the respondents. Most of the respondents showed positive attitude towards disease seriousness and believed that the disease could be cured and can be treated through modern medicines. Admission to hospitals, cleanliness and use of bed nets were the treatment measures for the disease in suspected patients, whereas some believed that the use of bed nets could be helpful in preventing the leishmaniasis. Moderate knowledge of the CL and its transmission in the study area emphasize the need to initiate health education and awareness campaigns to reduce the disease risk and burden in this highly endemic area in near future.
|
|
| 4. |
- Johansson Wensman, Jonas
(författare)
-
Expansion in host dynamics of peste des petits ruminants: Potential attribute of outbreaks in disease-endemic settings
- 2022
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X .- 1873-6254. ; 234
-
Tidskriftsartikel (refereegranskat)abstract
- Since the first case report in 1942, the peste-des-petits-ruminants virus (PPRV) has been causing infection in a wide range of susceptible hosts, particularly in disease-endemic regions. In the last 40 years, various reports highlighted the evidence of disease and viral genome in around 46 animal species from nine diverse families, including Bovidae, Cervidae, Camelidae, Suidae, Canidae, Felidae, Muridae, and Elephantidae. This evidence of clinical and/ or subclinical infection and the presence of the virus in an extended range of susceptible hosts emphasizes the cross-species transmission that remains a significant obstacle to effective control, particularly in disease-endemic regions. Therefore, a better understanding of virus transmission, host susceptibility, and epidemiological investigation of the disease is crucial to achieving the goals of efficient disease control and eradication programs initiated by OIE and FAO in various diseases-endemic regions. Nevertheless, the propensity of PPRV to inter- and intra-transmission may be a possible constraint in disease control strategies in terms of the new outbreak with the involvement of unusual or novel hosts. Considering this aspect, we tried to summarize the scattered data on PPR in available information about the susceptibility of a wide range of wildlife species, large ruminants, camels, and unusual hosts.
|
|
| 5. |
- Johansson Wensman, Jonas
(författare)
-
Sentinel surveillance of selected veterinary and public health pathogens in camel population originating from Southern Punjab province, Pakistan
- 2020
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X .- 1873-6254. ; 205
-
Tidskriftsartikel (refereegranskat)abstract
- An extended range of host susceptibility including camel has been evidenced for some of the important veterinary and public health pathogens, such as brucellosis, peste des petits ruminants (PPR) and bluetongue (BT). However, in disease endemic settings across many parts of the globe, most of the disease control interventions accounts for small and large ruminants, whereas unusual hosts and/or natural reservoirs, such as camels, remain neglected for disease control measures including routine vaccination. Such a policy drawback not only plays an important role in disease epizootiology particularly in settings where disease is endemic, but also serves an obstacle in disease control and subsequent eradication in future. With this background, using pre-validated ELISA and molecular assays [multiplex PCR, reverse transcriptase (RT)-PCR and real-time (rt)-PCR], we conducted a large-scale pathogen- and antibody-based surveillance for brucellosis, peste des petits ruminants and bluetongue in camel population (n = 992) originating from a wide geographical region in southern part of the Punjab province, Pakistan. Varying in each of the selected districts, the seroprevalence was found to be maximum for bluetongue [n=697 (70.26%, 95% CI: 67.29-73.07)], followed by PPR [n = 193 (19.46%, 95% CI: 17.07-22.09)] and brucellosis [n = 66 (6.65%, 95% CI: 5.22-8.43)]. Odds of seroprevalence were more significantly associated with pregnancy status (non-pregnant, OR = 2.23, 95% CI: 1.86-5.63, p<0.01), farming system (mixed-animal, OR = 2.59, 95% CI: 1.56-4.29, p<0.01), breed (Desi, OR = 1.97, 95% CI: 1.28-4.03, p<0.01) and farmer education (illiterate, OR= 3.17, 95% CI: 1.45-6.93, p<0.01) for BTV, body condition (normal, OR = 3.54, 95% CI: 1.92-6.54, p<0.01) and breed (Desi, OR = 2.19, 95% CI: 1.09-4.40, p<0.01) for brucellosis, and feeding system for PPR (grazing, OR = 2.75, 95% CI: 1.79-4.22, p<0.01). Among the total herds included (n = 74), genome corresponding to BT virus (BTV) and brucellosis was detected in 14 (18.92%, 95 CI: 11.09-30.04) and 19 herds (25.68%, 95% CI: 16.54-37.38), respectively. None of the herds was detected with genome of PPR virus (PPRV). Among the positive herds, serotype 1, 8 and 11 were detected for BTV while all the herds were exclusively positive to B. abortus. Taken together, the study highlights the role of potential disease reservoirs in the persistence and transmission of selected diseases in their susceptible hosts and, therefore, urges necessary interventions (e.g., inclusion of camels for vaccine etc.) for the control of diseases from their endemic setting worldwide.
|
|
| 6. |
- Lagunas-Rangel, Francisco Alejandro, et al.
(författare)
-
Ribosomal DNA in the protozoan parasite Giardia duodenalis has a differential chromatin distribution and epigenetic markings across the subunits
- 2021
-
Ingår i: Acta Tropica. - : Elsevier BV. - 0001-706X .- 1873-6254. ; 217
-
Tidskriftsartikel (refereegranskat)abstract
- Giardia duodenalis is a parasite that causes a large number of diarrheal diseases around the world. It is noteworthy that in a large number of processes, Giardia requires fewer components than other eukaryotes, even without some organelles such as mitochondria and peroxisomes. Despite this, core histones are known to exist in Giardia and epigenetic marks have been found on them, suggesting that they somehow control the expression of certain genes. The regulation of the expression of ribosomal DNA (rDNA) is essential, since it is required to maintain adequate levels of ribosomes and, given the nature of tandem repeat, it is a feasible area to create genomic instability. In Giardia, it is not known how this process occurs, but as in other eukaryotes, it is suggested through various epigenetic mechanisms. Thus, in the present work we seek to identify how chromatin is distributed through the Giardia rDNA and if there were histone marks that could control its expression.
|
|
| 7. |
- Lysholm, Sara, et al.
(författare)
-
Seropositivity rates of zoonotic pathogens in small ruminants and associated public health risks at informal urban markets in Zambia
- 2022
-
Ingår i: Acta Tropica. - : Elsevier. - 0001-706X .- 1873-6254. ; 225
-
Tidskriftsartikel (refereegranskat)abstract
- Informal livestock markets are an important source of animal-derived proteins for growing urban populations in countries such as Zambia. In parallel, they can also constitute pathways of zoonotic pathogen transmission to humans. This risk is aggravated by limited disease monitoring and poor control systems with regards to biosecurity and public health. The aim of this study was to investigate the risks for spread of zoonotic diseases in Zambia's two largest informal small ruminant markets, located in Lusaka and Kasumbalesa, through combining seroepidemiology with interviews and observations. In April, May and September 2018, serum samples (n = 237) were collected and analysed for antibodies for the zoonotic pathogens Brucella spp., Coxiella (C.) burnetii and Rift Valley fever virus (RVFV), using commercially available enzyme linked immunosorbent assays (ELISA). In addition, slaughterhouse activities were observed and semi-structured interviews and focus group discussions held with slaughterhouse workers and small ruminant traders, focusing on the handling of animals and meat, and the perceptions of zoonotic disease risks at slaughter and consumption. The study found seropositivity rates of 10.1% (95% confidence interval [CI] 6.60–14.7) for Brucella spp., 5.9% (95% CI 3.27–9.71) for C. burnetii, and 0.8% (95% CI 0.10–3.01) for RVFV. Interviews with value chain members and observations at the slaughterhouse revealed unsanitary procedures and multiple occupational hazards for slaughterhouse workers. This study showed that the Zambian informal small ruminant trade system poses risks to public health, and that these risks are exacerbated by a lack of information about food-borne diseases and how associated risks can be mitigated amongst value chain actors. The results of this study can be used to formulate preventive measures to improve informal meat markets and reduce the risks to public health.
|
|
| 8. |
|
|
| 9. |
- Roblejo-Arias, Lisset, et al.
(författare)
-
First molecular evidence of Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ infections and its association with epidemiological factors in dogs from Cuba
- 2022
-
Ingår i: Acta Tropica. - : Elsevier. - 0001-706X .- 1873-6254. ; 228
-
Tidskriftsartikel (refereegranskat)abstract
- Haemotrophic mycoplasmas (haemoplasmas) are unculturable, epicellular, cell wall-less gram-negative bacteria distributed worldwide, which infect several mammalian species. In dogs, Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ have been reported as causative agents of infectious anaemia, especially in splenectomised or immunocompromised animals. The present cross-sectional study aims to assess the prevalence, risk factors, and molecular characterization of canine haemoplasmas in Cuba. A total of 391 dog blood samples and 247 tick samples were tested for the presence of canine haemoplasmas by species-specific quantitative TaqMan® real-time PCR assays. Overall, 17.9% (70/391; 95% CI: 14.1–21.7) blood samples were PCR-positive for at least one canine haemoplasmas species, where 15.1% (59/391; 95% CI: 11.5–18.7) for Mycoplasma haemocanis, 4.4% (17/391; 95% CI: 2.3–6.4) for ‘Candidatus Mycoplasma haematoparvum’, and 1.5% (6/391; 95% CI: 0.3–2.8) were co-infected. All collected ticks were identified morphologically as Rhipicephalus sanguineus sensu lato, and none of the tested tick samples was found PCR-positive for the presence of Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’. Risk factors for canine haemoplasmas species infection included the presence of tick infestation, crossbreeding and living in kennels, while no association was found with the occurrence of anaemia. Phylogenetic analyses based on the 16S rRNA gene sequences of Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ revealed >99% identity to other isolates distributed worldwide, indicating low genetic variability amongst these canine haemoplasmas species. To the best of the authors´ knowledge, this is the first molecular evidence of Mycoplasma haemocanis and ‘Candidatus Mycoplasma haematoparvum’ infections in dogs from Cuba.
|
|
| 10. |
- Torrico, Mary Cruz, et al.
(författare)
-
The need for culture in tegumentary leishmaniasis diagnosis in Bolivia : a comparative evaluation of four parasitological techniques using two sampling methods
- 2024
-
Ingår i: Acta Tropica. - : Elsevier. - 0001-706X .- 1873-6254. ; 250
-
Tidskriftsartikel (refereegranskat)abstract
- Leishmaniases are zoonotic diseases caused by protozoa of the genus Leishmania. In Bolivia, leishmaniasis occurs mainly in the cutaneous form (CL) followed by the mucosal or mucocutaneous form (ML or MCL), grouped as tegumentary leishmaniosis (TL), while cases of visceral leishmaniasis (VL) are rare. The cases of TL are routinely diagnosed by parasitological methods: Direct Parasitological Exam (DPE) and axenic culture, the latter being performed only by specialized laboratories. The aim of the present study was to optimize the parasitological diagnosis of TL in Bolivia, using two sampling methods. Samples from 117 patients with suspected TL, obtained by aspiration (n = 121) and scraping (n = 121) of the edge of the lesion were tested by: direct parasitological exam, culture in TSTB medium, and miniculture and microculture in Schneider's medium. A positive laboratory result by any of the four techniques evaluated using either of the two sampling methods was considered the gold standard. Of the 117 suspected patients included, TL was confirmed in 96 (82 %), corresponding 79 of the confirmed cases (82.3 %) to CL and 16 (16.7 %) to ML. Parasitological techniques specificity was 100 % and their analytical sensitivity was greater with scraping samples in TSTB culture (98 %). Scraping samples in TSTB and miniculture correlated well with the reference (Cohen's kappa coefficient=0.88) and showed good reliability (Cronbach's alpha coefficient ≥0.91). Microculture provided positive results earlier than the other culture methods (mean day 4.5). By day 14, 98 % of positive cultures had been detected. Scraping sampling and miniculture were associated with higher culture contamination (6 % and 17 %, respectively). Bacterial contamination predominated, regardless of the sampling and culture method, while filamentous fungi and mixed contamination were more frequently observed in cultures from scraping samples. In conclusion: (i) scraping samples proved more suitable for the diagnosis of TL as they increased analytical sensitivity, are less traumatic for the patient and are safer for laboratory personnel than aspirates; (ii) culture, mainly in TSBT medium, should be used for the diagnosis of TL due to its high sensitivity (doubling the number of cases diagnosed by DPE) and its low cost compared to other culture media.
|
|
