Incremental effect of natural tick challenge on the infection and treatment method-induced immunity against T. parva in cattle under agro-pastoral systems in Northern Tanzania

Kazungu, Yvette; Mwega, Elisa; Neselle, M.O.; Sallu, Raphael; Kimera, Sharadhuli I.; Gwakisa, Paul

doi:10.1016/j.ttbdis.2015.04.014

Cited by 17 publications

(17 citation statements)

References 20 publications

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“…The 100% seroprevalence indicates that all study animals had previous exposure to T. parva, although differences existed between the strains and individual cattle in terms of level of antibodies produced. The high seroprevalence obtained in this study area further demonstrates the potential development of a state of endemic stability in the Lake zone, whereby the majority of cattle are expected to be carriers as previously shown by Kazungu et al (2015). Dipping regime did not show any influence on seroprevalence results.…”

Section: Discussionsupporting

confidence: 78%

“…Zebu cattle usually acquire immunity to T. parva following recovery after primary ECF infection. It is also evidently reported that natural tick challenge incrementally boosts the immunity acquired by zebu cattle kept in endemic areas (Kazungu et al, 2015), therefore, resistant individuals or breeds are likely to attain higher immunity compared to susceptible breeds. Our result on the differences between Tarime and Sukuma cattle strains further confirms the preference of farmers in the Lake Zone for Tarime cattle than other strains of cattle (Laisser et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

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Tick burden and acquisition of immunity to Theileria parva by Tarime cattle in comparison to Sukuma cattle under different tick control regimes in the Lake Zone of Tanzania

Laisser¹,

Chenyambuga²,

Karimuribo³

et al. 2016

J. Vet. Med. Anim. Health

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This study was conducted to determine tick burden and immunological parameters of resistance to East Coast fever (ECF) in Tarime and Sukuma cattle. Tick load, packed cell volume (PCV), Theileria parva (T. parva) specific antibody percent positivity (PP), and prevalence of T. parva parasites were studied in relation to dipping regime, strains, and season. A total of 50 experimental cattle were included in this study. Tick load was determined by whole body counts, antibody percent positivity was determined by the polymorphic immunodominant molecule (PIM)-based T. parva enzyme-linked immunosorbent assay (ELISA), and prevalence of T. parva parasites was detected by a nested polymerase chain reaction (PCR) based on the p104 gene. Dipping frequency on tick burden showed no statistically significant differences when cattle of either strain were dipped either once every 2 or 3 weeks in the dry and wet seasons. However, Tarime cattle had higher (p<0.05) tick count than Sukuma cattle and non dipped groups maintained high tick infestation throughout the experimental period. The PCV values were within the physiological range, although this parameter was lower in Tarime cattle (p<0.05). All cattle regardless of strain were seropositive, although Tarime cattle maintained higher PP compared to Sukuma by 15%. Conversely, the prevalence of T. parva parasites was lower in Tarime (38%) compared to Sukuma cattle (38.5%), but the difference was not significant (p>0.05). During the study period, 20% (5/25) of Sukuma cattle contracted ECF, but none of the Tarime cattle showed clinical signs for the disease. The differences between the two strains shown in terms of PP and T. parva parasite prevalence may indicate the ability of individual cattle to resist tick infestation and ECF infection under natural challenge. Higher antibody levels but lower parasite prevalence attained by Tarime cattle, suggests inherent ability of Tarime cattle to resist clinical development of ECF infection, but to remain as T. parva carriers.

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Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Tick burden and acquisition of immunity to Theileria parva by Tarime cattle in comparison to Sukuma cattle under different tick control regimes in the Lake Zone of Tanzania

Laisser¹,

Chenyambuga²,

Karimuribo³

et al. 2016

J. Vet. Med. Anim. Health

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“…Long‐term persistence of the carrier state up to 14 years is probably a combined effect of the vaccination and the continuous natural tick challenge that pastoralist cattle are exposed to, as was the case in the present study. Previously, we showed that tick exposure plays a major role in form of an incremental booster effect on the ITM‐induced immunity (Kazungu et al, ). Furthermore, PCR‐based detection of the Muguga vaccine marker, the minisatellite MS7, in cattle, particularly those vaccinated 14 years previously further provides evidence of long‐term persistence of the carrier state post‐vaccination.…”

Section: Discussionmentioning

confidence: 99%

Monitoring vaccinated cattle for induction and longevity of persistent tick‐transmissible infection: Implications for wider deployment of live vaccination against East Coast fever in Tanzania

Gwakisa

Kindoro

Mwega

et al. 2020

Transbound Emerg Dis

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The infection and treatment (ITM) procedure remains the only available method of immunization against Theileria parva infection. One constraint to deployment is the perception that the carrier state induced by ITM could result in enhanced disease problems. More than one million cattle have been ITM vaccinated in pastoralist systems in Tanzania over the last 2 decades. We present the results of a longitudinal study of six groups of cattle in Maasai villages in northern Tanzania exposed to natural tick challenge for between 2 weeks and 14 years post‐vaccination. The p104 nested PCR revealed a higher frequency of T. parva carriers among vaccinates (30%) compared with controls (8%) (OR = 4.89, p = .000), with the highest frequency of carriers found in calves vaccinated 6 months previously, although carrier state was also detected in cattle vaccinated >10 years prior to the study. Variable number tandem repeat genotype analysis revealed 6 MS7 alleles with sizes ranging from 150 bp to 500 bp, but only two alleles were detected in cattle vaccinated >4 years earlier, relative to five alleles detected in recently vaccinated cattle and controls. In terms of heterozygosity, diversity was maximal in calves vaccinated within the last 2 weeks (h = 0.776) but lowest in cattle vaccinated 4 years earlier (h = 0.375). The analysis suggested close genetic relatedness of parasites in vaccinated and unvaccinated groups and up to 96% of variation was within rather than between the groups. These results confirm that ITM leads to a long‐term T. parva carrier state in cattle and the detection of vaccine component VNTR in co‐grazing unvaccinated cattle suggests potential vaccine transmission by ticks. However, vaccination stocks did not totally replace local genotypes, at least in cattle populations. These findings should mitigate concerns that ITM modifies T. parva field populations in a way that enhances disease in the medium term.

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“…It is generally considered that distribution of T. parva is primarily limited by the tick vector which is in turn determined by climate (Norval et al, 1992). Oura, Tait, Asiimwe, Lubega, and Weir (2011b) On a different theme, but likely relevant to the success of ITM in northern Tanzania, a study of vaccinated cattle and unvaccinated control cattle adjacent to Tarangire National Park (Kazungu et al, 2015) revealed an incremental increase in seropositivity, assessed by PIM ELISA, the closer cattle were to the park. Theileria parva prevalence using p104 nested PCR was also higher closer to the park.…”

Section: P Opul Ati On G Ene Ti C S and D Is Tributi On Of The Ti Cmentioning

confidence: 99%

A review of recent research on Theileria parva : Implications for the infection and treatment vaccination method for control of East Coast fever

Bishop

Odongo

Ahmed

et al. 2020

Transbound Emerg Dis

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The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can ‘breakthrough’ the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co‐graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T‐cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long‐term consequences are unknown.

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Incremental effect of natural tick challenge on the infection and treatment method-induced immunity against T. parva in cattle under agro-pastoral systems in Northern Tanzania

Cited by 17 publications

References 20 publications

Tick burden and acquisition of immunity to Theileria parva by Tarime cattle in comparison to Sukuma cattle under different tick control regimes in the Lake Zone of Tanzania

Tick burden and acquisition of immunity to Theileria parva by Tarime cattle in comparison to Sukuma cattle under different tick control regimes in the Lake Zone of Tanzania

Monitoring vaccinated cattle for induction and longevity of persistent tick‐transmissible infection: Implications for wider deployment of live vaccination against East Coast fever in Tanzania

A review of recent research on Theileria parva : Implications for the infection and treatment vaccination method for control of East Coast fever

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